#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;

#define OVERLOAD_REP(_1, _2, _3, _4, name, ...) name
#define REP1(i, n) for (auto i = std::decay_t<decltype(n)>{}; (i) < (n); ++(i))
#define REP2(i, l, r) for (auto i = (l); (i) < (r); ++(i))
#define REP3(i, l, r, d) for (auto i = (l); (i) < (r); i += (d))
#define rep(...) OVERLOAD_REP(__VA_ARGS__, REP3, REP2, REP1)(__VA_ARGS__)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define YesNo(b) ((b) ? "Yes" : "No")
#define YESNO(b) ((b) ? "YES" : "NO")
#define yesno(b) ((b) ? "yes" : "no")

using mint = modint998244353;
using ull = unsigned long long;
using ll = long long;
using vi = vector<int>;
using vll = vector<ll>;
using vb = vector<bool>;
using vvi = vector<vi>;
using vvll = vector<vll>;
using vs = vector<string>;
using vvs = vector<vs>;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vpii = vector<pii>;
const vi dx = {1, 0, -1, 0};
const vi dy = {0, 1, 0, -1};
constexpr int INF = 1 << 30;
constexpr ll LINF = 1LL << 60;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n = 5e8;
    while (true) {
        cout << n << endl;
        int r;
        cin >> r;
        if (r == 1 || r == -1) break;
        n++;
        n /= 2;
    }
}