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

#define ll long long

int N, W;
int V[1005], WW[1005];
int main()
{
  cin >> N >> W;
  for (int i=0; i < N; i++)
    cin >> V[i] >> WW[i];

  int mx = -1;
  for (int i = 0; i < N; i++)
    if (W >= WW[i])
      mx = max(mx, V[i]);

  cout << mx << endl;
}