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