#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, h, total = 0;
  scanf("%lld %lld", &n, &h);
  vector<long long> a(n), b(n);
  for (long long i = 0; i < n; i++) {
    scanf("%lld %lld", &a[i], &b[i]);
  }
  sort(a.begin(), a.end(), greater<long long>());
  sort(b.begin(), b.end(), greater<long long>());
  for (long long i = 0; h >= 0; total++) {
    if (i < n && a[0] < b[i]) {
      h -= b[i];
      i++;
    } else {
      total += h / a[0] + (h % a[0] ? 1 : 0);
      break;
    }
  }
  printf("%lld\n", total);
}
