#include <iostream>
#include <algorithm>
using namespace std;

int main() {
    int N, W;
    cin >> N >> W;
    int res = -1;
    for (int i = 0; i < N; ++i) {
        int v, w;
        cin >> v >> w;
        if (w <= W) {
            res = max(res, v);
        }
    }
    cout << res << endl;
    return 0;
}