#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int n, h, a[200005], b[200005], ax = 0, cou = 0;
  cin >> n >> h;
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
    if (ax < a[i]) {
      ax = a[i];
    }
  }
  sort(b, b + n);
  for (int i = 0; i < n; i++) {
    if (ax < b[i]) {
      cou++;
      h -= b[i];
    }
    if (h <= 0) {
      cout << cou;
      return 0;
    }
  }
  cout << cou + (h - 1) / ax + 1;
}
