#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
  #define _GLIBCXX_DEBUG
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned 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) {
      ans = max(ans, v);
    }
  }
  cout << ans << endl;
  return 0;
}