#include <bits/stdc++.h>
#ifdef local
#include "debug.hpp"
#endif
using namespace std;

int main(void) {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    constexpr char endl = '\n';

    int n, W;
    cin >> n >> W;

    vector<int> v(n), w(n);
    for (int i = 0; i < n; i++) {
        cin >> v[i] >> w[i];
    }
    
    int ans = -1;
    for (int i = 0; i < n; i++) {
        if (w[i] <= W) ans = max(ans, v[i]);
    }
    
    cout << ans << endl;

    return 0;
}