#include <bits/stdc++.h>
using namespace std;
int main(void) {
  int n, h;
  cin >> n >> h;
  int a = 0, b[n];
  for (int i = 0; i < n; i++) {
    int t;
    cin >> t >> b[i];
    a = max(t, a);
  }
  sort(b, b + n);
  int p = n - 1;
  while (b[p] > a && h > 0) h -= b[p--];
  cout << n - 1 - p + (h + a - 1) / a;
}
