#if !__INCLUDE_LEVEL__

#include __FILE__
int main() {
    int N,W;cin >> N >> W;
    ll Ans = -1;
    rep(i,N){
        ll v,w;cin >> v >> w;
        if(w<=W)chmax(Ans,v);
    }
    cout << Ans << "\n";
}

#else
// tie(a, b, c) = t
// repをllにしているので時間ギリギリならintに変換
#include <bits/stdc++.h>

#include <atcoder/all>
using namespace std;
using namespace atcoder;
#define rep(i, n) for (long long int i = 0; i < n; i++)
#define rrep(i, n) for (long long int i = n - 1; i >= 0; i--)
#define range(i, m, n) for (long long int i = m; i < n; i++)
#define fore(i, a) for (auto &i : a)
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define Sum(v) accumulate(all(v), 0LL)
#define minv(v) *min_element(all(v))
#define maxv(v) *max_element(all(v))
#define fi first
#define se second
typedef long long ll;
typedef vector<ll> vl;
typedef vector<vector<ll> > vvl;
const ll INF = 1LL << 60;
const ll MOD1 = 1000000007;
const ll MOD2 = 998244353;
template <class T>
inline bool chmax(T &a, T b) {
    if (a < b) {
        a = b;
        return 1;
    }
    return 0;
}
template <class T>
inline bool chmin(T &a, T b) {
    if (a > b) {
        a = b;
        return 1;
    }
    return 0;
}
ll SN(char s) { return ll(s - '0'); }
ll SN(string s) { return stoll(s); }
int alpN(char s) { return int(s - 'a'); }
int AlpN(char s) { return int(s - 'A'); }
int Nalp(int n) { return char(n + 97); }
int NAlp(int n) { return char(n + 65); }
using mint = modint;
using mint1 = modint1000000007;
using mint2 = modint998244353;
using pll = pair<long long, long long>;
template <class T>
ostream &operator<<(ostream &o, const vector<T> &v) {
    for (int i = 0; i < (int)v.size(); i++) o << (i > 0 ? " " : "") << v[i];
    return o;
}  // vector空白区切り出力
template <class T, class U>
ostream &operator<<(ostream &o, pair<T, U> &p) {
    o << "(" << p.first << ", " << p.second << ")";
    return o;
}
ostream &operator<<(ostream &os, const mint1 &N) {
    return os << N.val();
}  // mint出力。デフォはmint1
ostream &operator<<(ostream &os, const mint2 &N) { return os << N.val(); }
template <class T>
bool contain(const std::string &s, const T &v) {
    return s.find(v) != std::string::npos;
}
ll max(int x, ll y) { return max((ll)x, y); }
ll max(ll x, int y) { return max(x, (ll)y); }
ll min(int x, ll y) { return min((ll)x, y); }
ll min(ll x, int y) { return min(x, (ll)y); }
template <typename T = int>
struct Edge {
    int from, to;
    T cost;
    int idx;

    Edge() = default;

    Edge(int from, int to, T cost = 1, int idx = -1)
        : from(from), to(to), cost(cost), idx(idx) {}

    operator int() const { return to; }
};

template <typename T = int>
struct Graph {
    vector<vector<Edge<T> > > g;
    int es;

    Graph() = default;

    explicit Graph(int n) : g(n), es(0) {}

    size_t size() const { return g.size(); }

    void add_directed_edge(int from, int to, T cost = 1) {
        g[from].emplace_back(from, to, cost, es++);
    }

    void add_edge(int from, int to, T cost = 1) {
        g[from].emplace_back(from, to, cost, es);
        g[to].emplace_back(to, from, cost, es++);
    }

    void read(int M, int padding = -1, bool weighted = false,
              bool directed = false) {
        for (int i = 0; i < M; i++) {
            int a, b;
            cin >> a >> b;
            a += padding;
            b += padding;
            T c = T(1);
            if (weighted) cin >> c;
            if (directed)
                add_directed_edge(a, b, c);
            else
                add_edge(a, b, c);
        }
    }

    inline vector<Edge<T> > &operator[](const int &k) { return g[k]; }

    inline const vector<Edge<T> > &operator[](const int &k) const {
        return g[k];
    }
};

template <typename T = int>
using Edges = vector<Edge<T> >;
template <typename T>
using Matrix = vector<vector<T> >;

// unorderd_mapの拡張…https://qiita.com/hamamu/items/4d081751b69aa3bb3557
template <class T>
size_t HashCombine(const size_t seed, const T &v) {
    return seed ^ (std::hash<T>()(v) + 0x9e3779b9 + (seed << 6) + (seed >> 2));
}
/* pair用 */
template <class T, class S>
struct std::hash<std::pair<T, S> > {
    size_t operator()(const std::pair<T, S> &keyval) const noexcept {
        return HashCombine(std::hash<T>()(keyval.first), keyval.second);
    }
};
/* vector用 */
template <class T>
struct std::hash<std::vector<T> > {
    size_t operator()(const std::vector<T> &keyval) const noexcept {
        size_t s = 0;
        for (auto &&v : keyval) s = HashCombine(s, v);
        return s;
    }
};
/* tuple用 */
template <int N>
struct HashTupleCore {
    template <class Tuple>
    size_t operator()(const Tuple &keyval) const noexcept {
        size_t s = HashTupleCore<N - 1>()(keyval);
        return HashCombine(s, std::get<N - 1>(keyval));
    }
};
template <>
struct HashTupleCore<0> {
    template <class Tuple>
    size_t operator()(const Tuple &keyval) const noexcept {
        return 0;
    }
};
template <class... Args>
struct std::hash<std::tuple<Args...> > {
    size_t operator()(const tuple<Args...> &keyval) const noexcept {
        return HashTupleCore<tuple_size<tuple<Args...> >::value>()(keyval);
    }
};
ll ceil(ll a, ll b) { return (a + b - 1) / b; }
struct string_converter {
    char start = 0;
    char type(const char &c) const {
        return (islower(c) ? 'a' : isupper(c) ? 'A' : isdigit(c) ? '0' : 0);
    }
    int convert(const char &c) {
        if (!start) start = type(c);
        return c - start;
    }
    int convert(const char &c, const string &chars) { return chars.find(c); }
    template <typename T>
    auto convert(const T &v) {
        vector<decltype(convert(v[0]))> ret;
        ret.reserve(v.size());
        for (auto &&e : v) ret.emplace_back(convert(e));
        return ret;
    }
    template <typename T>
    auto convert(const T &v, const string &chars) {
        vector<decltype(convert(v[0], chars))> ret;
        ret.reserve(v.size());
        for (auto &&e : v) ret.emplace_back(convert(e, chars));
        return ret;
    }
    int operator()(const char &v, char s = 0) {
        start = s;
        return convert(v);
    }
    int operator()(const char &v, const string &chars) {
        return convert(v, chars);
    }
    template <typename T>
    auto operator()(const T &v, char s = 0) {
        start = s;
        return convert(v);
    }
    template <typename T>
    auto operator()(const T &v, const string &chars) {
        return convert(v, chars);
    }
} toint;
#endif