#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
#include <random>

using namespace std;

using ll = long long;

template <typename T>
struct Edge
{
    int From;
    int To;
    T Weight;

public:
    Edge(int from, int to, T weight)
    {
        From = from;
        To = to;
        Weight = weight;
    }
};

struct Point 
{
public:
    int X;
    int Y;

    Point(int x, int y)
    {
        X = x;
        Y = y;
    }

    friend bool operator==(Point left, Point right)
    {
        return left.X == right.X && left.Y == right.Y;
    }

    friend bool operator<(Point left, Point right)
    {
        return tie(left.X, left.Y) < tie(right.X, right.Y);
    }
};

struct PointHash
{
    size_t operator()(Point point)
    {
        return hash<int>()(point.X) ^ hash<int>()(point.Y);
    }
};

template <typename T>
struct RunLengthElement
{
public:
    int Count;
    int StartIndex;
    T Value;

    RunLengthElement(int startIndex, int count, T value)
    {
        StartIndex = startIndex;
        Count = count;
        Value = value;
    }
};

template <typename T>
bool reverseCompare(T a, T b)
{
    return a > b;
}

vector<int> vectorInt(int n)
{
    vector<int> res;
    res.reserve(n);
    for (int i = 0; i < n; i++)
    {
        int v;
        cin >> v;
        res.push_back(v);
    }

    return res;
}

vector<ll> vectorLong(int n)
{
    vector<ll> res;
    res.reserve(n);
    for (int i = 0; i < n; i++)
    {
        ll v;
        cin >> v;
        res.push_back(v);
    }

    return res;
}

vector<string> vectorString(int n)
{
    vector<string> res;
    res.reserve(n);
    for (int i = 0; i < n; i++)
    {
        string v;
        cin >> v;
        res.push_back(v);
    }

    return res;
}

int combination(int n, int r)
{
    int c = 1;
    for (int i = 1; i <= r; i++)
    {
        c = c * (n - i + 1) / i;
    }
    return c;
}

ll combination(ll n, ll r)
{
    ll c = 1;
    for (ll i = 1; i <= r; i++)
    {
        c = c * (n - i + 1) / i;
    }
    return c;
}

ll pow(ll b, ll exp)
{
    if (exp == 0) return 1L;
    if (exp == 1) return b;

    ll m = pow(b, exp / 2L);
    m *= m;
    if (exp % 2L == 1) m *= b;

    return m;
}

ll modpow(ll b, ll exp, ll mod)
{
    if (exp == 0) return 1;
    if (exp == 1) return b % mod;

    ll m = modpow(b, exp / 2L, mod);
    m *= m;
    m %= mod;
    if (exp % 2L == 1) m *= b % mod;
    m %= mod;

    return m;
}

ll modinv( ll a, ll mod )
{
    ll b = mod, u = 1, v = 0;
    while ( b > 0 )
    {
        ll t = a / b;
        a -= t * b; swap( a, b );
        u -= t * v; swap( u, v );
    }
    u %= mod;
    if (u < 0) u += mod;
    return u;
}

// ax ≡ b (mod m)なる最小のxを求める
optional<ll> solveModLinear(ll a, ll b, ll m)
{
    long gcd = __gcd(__gcd(a, b), m);
    a /= gcd;
    b /= gcd;
    m /= gcd;
    if (__gcd(a, m) == 1)
    {
        long inv = modinv(a, m);
        return make_optional((b * inv) % m);
    }

    return optional<ll>();
}

inline void YesNo(bool t)
{
    cout << (t ? "Yes" : "No") << endl;
}

inline void YESNO(bool t)
{
    cout << (t ? "YES" : "NO") << endl;
}

inline void yesno(bool t)
{
    cout << (t ? "yes" : "no") << endl;
}

inline bool checkBit(int bit, int n)
{
    return ((1 << n) & bit) != 0;
}

map<char, int> cntCharOcc(string s)
{
    map<char, int> dict;
    for (int i = 0; i < (int)s.size(); i++)
    {
        if (dict.find(s[i]) != dict.end())
        {
            dict[s[i]] += 1;
        }
        else
        {
            dict[s[i]] = 1;
        }
    }

    return dict;
}

template<typename T> bool chmin(T& a, T b)
{
    if(a > b)
    {
        a = b;
        return true;
    }
    return false;
}

template<typename T> bool chmax(T& a, T b)
{
    if(a < b)
    {
        a = b;
        return true;
    } 
    return false;
}

int get_random(int min, int max)
{
    max--;
    random_device rd;
    mt19937 mt(rd());
    uniform_int_distribution<> rand(min, max);
    return rand(mt);
}

template <typename T>
void shuffle(vector<T>& array)
{
    for (int i = (int)array.size() - 1; i > 0; i--)
    {
        int index = get_random(0, i + 1);
        swap(array[index], array[i]);
    }
}

template <typename T>
vector<int> compressCoords(vector<T>& array)
{
    vector<T> sorted = array;

    sort(sorted.begin(), sorted.end());
    auto r = unique(sorted.begin(), sorted.end());
    sorted.erase(r, sorted.end());

    vector<int> result(array.size());

    for (int i = 0; i < (int)array.size(); i++)
    {
        result[i] = lower_bound(sorted.begin(), sorted.end(), array[i]) - sorted.begin();
    }

    return result;
}

template <class _ForwardIterator>
vector<RunLengthElement<typename iterator_traits<_ForwardIterator>::value_type>> compressRunLength(_ForwardIterator first, _ForwardIterator last)
{
    vector<RunLengthElement<typename iterator_traits<_ForwardIterator>::value_type>> list;
    int count = 1;
    int start = 0;
    typename iterator_traits<_ForwardIterator>::value_type prev = *first;

    int curIndex = 1;

    first++;
    for (auto it = first; it != last; ++it)
    {
        if (prev == *it)
        {
            count++;
        }
        else
        {
            list.push_back(RunLengthElement<typename iterator_traits<_ForwardIterator>::value_type>(start, count, prev));
            start = curIndex;
            count = 1;
        }

        prev = *it;
        curIndex++;
    }

    list.push_back(RunLengthElement<typename iterator_traits<_ForwardIterator>::value_type>(start, count, prev));

    return list;
}

template <typename T>
vector<T> decompressRunLength(vector<RunLengthElement<T>>& source)
{
    vector<T> res;
    for (int i = 0; i < (int)source.size(); i++)
    {
        for (int j = 0; j < source[i].Count; j++)
        {
            res.push_back(source[i].Value);
        }
    }

    return res;
}

template <class _ForwardIterator>
void print(_ForwardIterator first, _ForwardIterator last)
{
    bool f = true;
    for (auto it = first; it != last; ++it)
    {
        if (!f)
        {
            cout << " ";
        }
        cout << *it;
        f = false;
    }

    cout << endl;
}

void print01(bool t)
{
    cout << (t ? "1" : "0") << endl;
}

bool isSquareNumber(ll n)
{
    ll q = (ll)floor(sqrt(n));
    return q * q == n;
}


// 最初から貼っとくライブラリ

template <typename T>
class PrefixSum
{
private:
    vector<T> _sums;

public:
    PrefixSum(vector<T>& sequence)
    {
        _sums.resize(sequence.size() + 1);

        _sums[0] = 0;
        for (int i = 0; i < (int)sequence.size(); i++)
        {
            _sums[i + 1] = _sums[i] + sequence[i];
        }
    }

    T Sum(int l, int r)
    {
        return _sums[r] - _sums[l];
    }

    T AllSum()
    {
        return _sums[_sums.size() - 1];
    }

    vector<T>& GetArray()
    {
        return _sums;
    }
};

template <typename T>
class PrefixSum2D
{
private:
    vector<vector<T>> _sums;

public:
    PrefixSum2D(vector<vector<T>>& sequence)
    {
        int height = sequence.size();
        int width = sequence[0].size();

        _sums.resize(height + 1, vector<T>(width + 1, 0));

        for (int y = 0; y < height; y++)
        {
            for (int x = 0; x < width; x++)
            {
                _sums[y + 1][x + 1] = _sums[y + 1][x] + _sums[y][x + 1] - _sums[y][x] + sequence[y][x];
            }
        }
    }

    T Sum(int startX, int startY, int endX, int endY)
    {
        return _sums[endY][endX] + _sums[startY][startX] - _sums[startY][endX] - _sums[endY][startX];
    }

    T AllSum()
    {
        return _sums[(int)_sums.size() - 1][(int)_sums[0].size() - 1];
    }
};

class UnionFind
{
private:
    vector<int> _parents;
    vector<int> _size;
    int _vertexCount;

public:
    UnionFind(int n)
    {
        _vertexCount = n;
        _parents.resize(n);
        _size.resize(n);
        for (int i = 0; i < n; i++)
        {
            _size[i] = 1;
            _parents[i] = i;
        }
    }

    int Root(int x)
    {
        if (_parents[x] == x) return x;
        
        return _parents[x] = Root(_parents[x]);
    }

    int Size(int x)
    {
        return _size[Root(x)];
    }

    void Unite(int x, int y)
    {
        int rootX = Root(x);
        int rootY = Root(y);

        if (rootX == rootY) return;

        int from = rootX;
        int to = rootY;

        if (_size[from] > _size[to])
        {
            swap(from, to);
        }

        _size[to] += _size[from];
        _parents[from] = to;
    }

    vector<int> Find(int x)
    {
        int root = Root(x);
        vector<int> set;
        for (int i = 0; i < _vertexCount; i++)
        {
            if (Root(i) == root)
            {
                set.push_back(i);
            }
        }

        return set;
    }

    unordered_map<int, vector<int>> FindAll()
    {
        unordered_map<int, vector<int>> sets;
        for (int i = 0; i < _vertexCount; i++)
        {
            int root = Root(i);
            if (sets.find(root) != sets.end())
            {
                sets[root].push_back(i);
            }
            else
            {
                sets.emplace(root, vector<int>());
                sets[root].push_back(i);
            }
        }

        return sets;
    }

    bool Same(int x, int y)
    {
        int rootX = Root(x);
        int rootY = Root(y);
        return rootX == rootY;
    }

    void Clear()
    {
        for (int i = 0; i < _vertexCount; i++)
        {
            _parents[i] = i;
            _size[i] = 1;
        }
    }

    int VertexCount()
    {
        return _vertexCount;
    }
};

template <typename T>
class Imos
{
private:
    vector<T> _data;

public:
    Imos(int length)
    {
        _data.resize(length, 0);
    }

    Imos(vector<T>& array)
    {
        _data = array;
    }

    void AddQueryLen(int start, int length, T value)
    {
        AddQuery(start, start + length, value);
    }

    void AddQuery(int start, int end, T value)
    {
        _data[start] += value;
        if (end < (int)_data.size())
        {
            _data[end] -= value;
        }
    }

    void Accumulate()
    {
        for (int i = 1; i < (int)_data.size(); i++)
        {
            _data[i] += _data[i - 1];
        }
    }

    vector<T> GetData()
    {
        return _data;
    }
};

template <typename T>
class Imos2D
{
private:
    vector<vector<T>> _data;
    int _width;
    int _height;

public:
    Imos2D(vector<vector<T>> data)
    {
        _data = data;
        _height = data.size();
        _width = data[0].size();
    }

    Imos2D(int h, int w)
    {
        _data.resize(h, vector<T>(w, 0));
        _width = w;
        _height = h;
    }

    void AddQuery(int startX, int startY, int endX, int endY, T value)
    {
        _data[startY][startX] += value;
        if (endX < _width)
        {
            _data[startY][endX] -= value;
        }
        if (endY < _height)
        {
            _data[endY][startX] -= value;
        }
        if (endX < _width && endY < _height)
        {
            _data[endY][endX] += value;
        }
    }

    void AddQueryLen(int x, int y, int w, int h, T value)
    {
        AddQuery(x, y, x + w, y + h, value);
    }

    void Accumulate()
    {
        for (int x = 1; x < _width; x++)
        {
            for (int y = 0; y < _height; y++)
            {
                _data[y][x] += _data[y][x - 1];
            }
        }

        for (int y = 1; y < _height; y++)
        {
            for (int x = 0; x < _width; x++)
            {
                _data[y][x] += _data[y - 1][x];
            }
        }
    }

    vector<vector<T>> GetData()
    {
        return _data;
    }
};

template<typename T, T OP(T, T), T APPLY(T, T)>
class SegmentTree
{
private:
    int _treeSize;
    int _dataSize;
    int _originalDataSize;
    vector<T> _data;
    T _identity;

public:
    SegmentTree(int n, T identity)
    {
        _originalDataSize = n;
        _identity = identity;

        int size = 1;
        while (n > size)
        {
            size <<= 1;
        }

        _dataSize = size;
        _treeSize = 2 * size - 1;

        _data.resize(_treeSize, _identity);
    }

    int OriginalDataSize()
    {
        return _originalDataSize;
    }

    int TreeSize()
    {
        return _treeSize;
    }

    T Identity()
    {
        return _identity;
    }

    void Build(vector<T>& array)
    {
        if (_originalDataSize != (int)array.size())
        {
            throw exception();
        }

        for (int i = 0; i < (int)array.size(); i++)
        {
            _data[i + _dataSize - 1] = array[i];
        }

        for (int i = _dataSize - 2; i >= 0; i--)
        {
            _data[i] = OP(_data[(i << 1) + 1], _data[(i << 1) + 2]);
        }
    }

    void Apply(int index, T value)
    {
        index += _dataSize - 1;
        _data[index] = APPLY(_data[index], value);

        while (index > 0)
        {
            index = (index - 1) >> 1;
            _data[index] = OP(_data[(index << 1) + 1], _data[(index << 1) + 2]);
        }
    }

    T Query(int left, int right)
    {
        return QueryRec(left, right, 0, 0, _dataSize);
    }

    const T& operator[](size_t index) const
    {
        return _data[_dataSize - 1 + index];
    }

    T& operator[](size_t index)
    {
        return _data[_dataSize - 1 + index];
    }

private:
    T QueryRec(int left, int right, int index, int l, int r)
    {
        if (left >= r || right <= l)
        {
            return _identity;
        }

        if (left <= l && r <= right)
        {
            return _data[index];
        }

        return OP(QueryRec(left, right, (index << 1) + 1, l, (l + r) / 2), QueryRec(left, right, (index << 1) + 2, (l + r) / 2, r));
    }
};

template <typename T, typename M, T OP(T, T), T MAPPING(T, M, int), T COMPOSITION(T, T)>
class LazySegmentTree
{
private:
    int _treeSize;
    int _dataSize;
    int _originalDataSize;
    vector<T> _data;
    vector<optional<T>> _lazy;
    T _identity;

public:
    LazySegmentTree(int n, T identity)
    {
        _originalDataSize = n;
        _identity = identity;

        int size = 1;
        while (n > size)
        {
            size <<= 1;
        }

        _dataSize = size;
        _treeSize = 2 * size - 1;

        _data.resize(_treeSize, _identity);
        _lazy.resize(_treeSize, nullopt);
    }

    void Build(vector<T>& array)
    {
        if (_originalDataSize != (int)array.size())
        {
            throw exception();
        }

        for (int i = 0; i < (int)array.size(); i++)
        {
            _data[i + _dataSize - 1] = array[i];
        }

        for (int i = _dataSize - 2; i >= 0; i--)
        {
            _data[i] = OP(_data[(i << 1) + 1], _data[(i << 1) + 2]);
        }
    }

    int TreeSize()
    {
        return _treeSize;
    }

    int OriginalDataSize()
    {
        return _originalDataSize;
    }

    void Apply(int left, int right, M m)
    {
        ApplyRec(left, right, m, 0, 0, _dataSize);
    }

    T Query(int left, int right)
    {
        return QueryRec(left, right, 0, 0, _dataSize);
    }

    T GetByIndex(int index)
    {
        if (index < 0 || index >= _originalDataSize)
        {
            throw exception();
        }

        return AccessRec(index, 0, 0, _dataSize);
    }

private:
    void Evaluate(int index, int l, int r)
    {
        if (!_lazy[index].has_value())
        {
            return;
        }

        if (index < _dataSize - 1)
        {
            _lazy[(index << 1) + 1] = GuardComposition(_lazy[(index << 1) + 1], _lazy[index]);
            _lazy[(index << 1) + 2] = GuardComposition(_lazy[(index << 1) + 2], _lazy[index]);
        }

        _data[index] = MAPPING(_data[index], _lazy[index].value(), r - l);
        _lazy[index] = nullopt;
    }

    optional<M> GuardComposition(optional<M> a, optional<M> b)
    {
        if (!a.has_value())
        {
            return b;
        }
        else
        {
            return COMPOSITION(a.value(), b.value());
        }
    }

    void ApplyRec(int left, int right, M m, int index, int l, int r)
    {
        Evaluate(index, l, r);

        if (left <= l && r <= right)
        {
            _lazy[index] = GuardComposition(_lazy[index], m);
            Evaluate(index, l, r);
        }
        else if (left < r && l < right)
        {
            ApplyRec(left, right, m, (index << 1) + 1, l, (l + r) / 2);
            ApplyRec(left, right, m, (index << 1) + 2, (l + r) / 2, r);
            _data[index] = OP(_data[(index << 1) + 1], _data[(index << 1) + 2]);
        }
    }

    T QueryRec(int left, int right, int index, int l, int r)
    {
        Evaluate(index, l, r);

        if (left >= r || right <= l)
        {
            return _identity;
        }

        if (left <= l && r <= right)
        {
            return _data[index];
        }

        return OP(QueryRec(left, right, (index << 1) + 1, l, (l + r) / 2), QueryRec(left, right, (index << 1) + 2, (l + r) / 2, r));
    }

    T AccessRec(int target, int index, int l, int r)
    {
        Evaluate(index, l, r);

        if (index >= _dataSize - 1)
        {
            return _data[index];
        }

        int mid = (l + r) / 2;
        
        if (target < mid)
        {
            return AccessRec(target, (index << 1) + 1, l, mid);
        }
        else
        {
            return AccessRec(target, (index << 1) + 2, mid, r);
        }
    }
};

#define CONST_MOD 998244353LL
//#define CONST_MOD 1000000007LL
struct ModInt
{
    long long Value;

public:
    ModInt()
    {
        Value = 0L;
    }

    ModInt(long long value)
    {
        Value = value;
    }

    ModInt Power(long long exp) const
    {
        if (exp <= -1L)
        {
            return ModInt(1L) / Power(-exp);
        }
        if (exp == 0L)
            return 1L;
        if (exp == 1L)
            return *this;

        ModInt m = Power(exp / 2L);
        m = m * m;
        if (exp % 2L == 1L)
        {
            m = m * (*this);
        }

        return m;
    }

    ModInt Inv() const
    {
        return this->Power(CONST_MOD - 2L);
    }

    ModInt operator+() const
    {
        return *this;
    }

    ModInt operator-() const
    {
        return ModInt(-Value);
    }

    friend ModInt operator+(const ModInt& left, const ModInt& right)
    {
        return ModInt(SafeMod(left.Value + right.Value));
    }

    friend ModInt operator+(const ModInt& left, const long long& right)
    {
        return ModInt(SafeMod(left.Value + right));
    }

    friend ModInt operator+(const long long& left, const ModInt& right)
    {
        return ModInt(SafeMod(left + right.Value));
    }

    ModInt& operator+=(const ModInt& x)
    {
        Value += x.Value;
        Value = SafeMod(Value);

        return *this;
    }

    ModInt& operator+=(const long long& x)
    {
        Value += x;
        Value = SafeMod(Value);

        return *this;
    }

    friend ModInt operator-(const ModInt& left, const ModInt& right)
    {
        return ModInt(SafeMod(left.Value - right.Value));
    }

    friend ModInt operator-(const ModInt& left, const long long& right)
    {
        return ModInt(SafeMod(left.Value - right));
    }

    friend ModInt operator-(const long long& left, const ModInt& right)
    {
        return ModInt(SafeMod(left - right.Value));
    }

    ModInt& operator-=(const ModInt& x)
    {
        Value -= x.Value;
        Value = SafeMod(Value);

        return *this;
    }

    ModInt& operator-=(const long long& x)
    {
        Value -= x;
        Value = SafeMod(Value);

        return *this;
    }

    friend ModInt operator*(const ModInt& left, const ModInt& right)
    {
        return ModInt(SafeMod(left.Value * right.Value));
    }

    friend ModInt operator*(const ModInt& left, const long long& right)
    {
        return ModInt(SafeMod(left.Value * right));
    }

    friend ModInt operator*(const long long& left, const ModInt& right)
    {
        return ModInt(SafeMod(left * right.Value));
    }

    ModInt& operator*=(const ModInt& x)
    {
        Value *= x.Value;
        Value = SafeMod(Value);

        return *this;
    }

    ModInt& operator*=(const long long& x)
    {
        Value *= x;
        Value = SafeMod(Value);

        return *this;
    }

    friend ModInt operator /(const ModInt& left, const ModInt& right)
    {
        ModInt inv = right.Inv();
        return ModInt(SafeMod(left.Value * inv.Value));
    }

    friend ModInt operator/(const ModInt& left, const long long& right)
    {
        return ModInt(SafeMod(left.Value * ModInt(right).Inv().Value));
    }

    friend ModInt operator/(const long long& left, const ModInt& right)
    {
        return ModInt(SafeMod(left * right.Inv().Value));
    }

    ModInt& operator/=(const ModInt& x)
    {
        Value *= x.Inv().Value;
        Value = SafeMod(Value);

        return *this;
    }

    ModInt& operator/=(const long long& x)
    {
        Value *= ModInt(x).Inv().Value;
        Value = SafeMod(Value);

        return *this;
    }

    ModInt& operator++()
    {
        ++Value;
        Value = SafeMod(Value);
        return *this;
    }

    ModInt operator++(int)
    {
        ModInt temp = *this;
        Value++;
        Value = SafeMod(Value);
        return temp;
    }

    ModInt& operator--()
    {
        --Value;
        Value = SafeMod(Value);
        return *this;
    }

    ModInt operator--(int)
    {
        ModInt temp = *this;
        Value--;
        Value = SafeMod(Value);
        return temp;
    }

    inline static ModInt One()
    {
        return ModInt(1L);
    }

    static ModInt Combination(long long n, long long r)
    {
        ModInt c = 1L;
        for (ModInt i = 1; i.Value <= r; i++)
        {
            c = c * (ModInt(n) - i + ModInt::One()) / i;
        }
        return c;
    }

private:
    inline static long long SafeMod(long long a)
    {
        a %= CONST_MOD;
        if (a < 0)
        {
            a += CONST_MOD;
        }
        return a;
    }
};

//

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    ll left = 1LL;
    ll right = 1000000000LL;

    while (right - left > 0)
    {
        ll mid = (left + right) / 2;

        cout << mid << endl;

        int r;
        cin >> r;
        if (r == 1)
        {
            left = mid + 1;
        }
        else
        {
            right = mid;
        }
    }
}