#include <bits/stdc++.h>
using namespace std;
int n, h, a[100010], b[100010], mx, ans;
int main() {
  cin >> n >> h;
  for (int i = 0; i < n; i++) cin >> a[i] >> b[i];
  sort(a, a + n, greater<int>());
  mx = a[0];
  sort(b, b + n, greater<int>());
  for (int i = 0; i < n; i++)
    if (b[i] > mx && h >= 0) {
      h -= b[i];
      ans++;
    }
  if (h >= 0) ans += (h + mx - 1) / mx;
  cout << ans;
  return 0;
}
