#include <bits/stdc++.h>
using namespace std;
int main() {
  int N, H;
  int a[100000], b[100000];
  cin >> N >> H;
  int max_a = 0;
  for (int i = 0; i < N; i++) {
    cin >> a[i] >> b[i];
    if (a[i] > max_a) max_a = a[i];
  }
  int cnt = 0;
  for (int i = 0; i < N; i++) {
    if (b[i] > max_a) {
      cnt++;
      H -= b[i];
    }
    if (H <= 0) {
      cout << cnt << endl;
      return 0;
    }
  }
  if (H % max_a == 0)
    cout << cnt + H / max_a << endl;
  else
    cout << cnt + H / max_a + 1 << endl;
  return 0;
}
