#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  int h;
  int i, t;
  long long cnt = 0;
  long long sum = 0;
  int max = -100100100;
  int a;
  int b[100006];
  scanf("%d %d", &n, &h);
  for (i = 0; i < n; i++) {
    scanf("%d %d", &a, &b[i]);
    if (max < a) max = a;
  }
  sort(b, b + n);
  for (i = n - 1; i >= 0; i++) {
    if (b[i] < max) break;
    h -= b[i];
    cnt++;
    if (h <= 0) break;
  }
  if (h > 0) {
    if (h % max == 0)
      cnt += h / max;
    else
      cnt += h / max + 1;
  }
  printf("%lld\n", cnt);
  return 0;
}
