#include <stdio.h>

int main () {
  int n = 0;
  int w = 0;
  int v = 0;
  int wi = 0;
  
  int res = 0;
  
  int ans = -1;
  
  res = scanf("%d", &n);
  res = scanf("%d", &w);
  for (int i = 0; i < n; i++) {
    res = scanf("%d", &v);
    res = scanf("%d", &wi);
    if (wi <= w && v > ans) {
      ans = v;
    }
  }
  
  printf("%d\n", ans);
  return 0;
}