#include <bits/stdc++.h>
using namespace std;
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  long long int N, H;
  cin >> N >> H;
  long long int max_a = 0, res = 0, B[N];
  for (long long int i = 0; i < N; ++i) {
    long long int a;
    cin >> a >> B[i];
    max_a = max(max_a, a);
  }
  for (long long int i = 0; i < N; ++i) {
    H -= max(max_a, B[i]);
    res++;
    if (H <= 0) {
      cout << res << endl;
      return 0;
    }
  }
  cout << res + (H % max_a == 0 ? H / max_a : H / max_a + 1) << endl;
}
