#include <bits/stdc++.h>
using namespace std;

#define rep(i, n) for( ll i = 0; i < n; i++ )
using ll = long long;

int main() {
	int N, W;
	cin >> N >> W;
	int ans = -1;
	rep(i, N) {
		int v, w;
		cin >> v >> w;
		if(w > W) continue;
		ans = max(ans, v);
	}
	cout << ans << endl;
}