#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); ++i)

using namespace std;
using ll = long long;
using P = pair<int, int>;

int main() {
    int n, W;
    cin >> n >> W;
    
    int ans = -1;
    rep(i, n) {
        int v, w;
        cin >> v >> w;
        if (w <= W) ans = max(ans, v);
    }
    
    cout << ans << '\n';
    
    return 0;
}