#include <iostream>
using namespace std;
int main(void){
    int N, W;
    cin >> N >> W;
    int ans = -1;
    int v, w;
    for (int i = 0; i < N; i++) {
        cin >> v >> w;
        if (w <= W) {
            ans = max(ans, v);
        }
    }
    cout << ans << endl;
}