#include <bits/stdc++.h>
int main() {
  long N, H;
  scanf("%ld %ld", &N, &H);
  long a[100001], b[100001];
  long a_max = 0, b_min = 1e9 + 1;
  for (long i = 0; i < N; i++) {
    scanf("%ld %ld", &a[i], &b[i]);
    if (a[i] > a_max) {
      a_max = a[i];
    }
    if (b[i] < b_min) {
      b_min = b[i];
    }
  }
  long ans = 0;
  for (long i = 0; i < N; i++) {
    if (a_max < b[i]) {
      H -= b[i];
      ans++;
      if (H < 0) {
        printf("%ld\n", ans);
        return 0;
      }
    }
  }
  while (H > 0) {
    H -= a_max;
    ans++;
  }
  printf("%ld\n", ans);
  return 0;
}
