#include <bits/stdc++.h>
using namespace std;
int main() {
  int N, H, a[100000], b[100000];
  cin >> N >> H;
  for (int i = 0; i < (N); i++) cin >> a[i] >> b[i];
  int a_max = *max_element(a, a + N);
  sort(b, b + N, greater<int>());
  int ans = 0, i = 0;
  while (H) {
    if (b[i] > a_max) {
      H -= b[i];
      ans++;
    } else
      break;
    i++;
  }
  ans += ceil((double)H / a_max);
  cout << ans << endl;
  return 0;
}
