#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, h;
  cin >> n >> h;
  vector<long long> a(n), b(n);
  long long max_a = 0;
  for (int i = 0; i < (n); i++) {
    cin >> a[i] >> b[i];
    max_a = max(max_a, a[i]);
  }
  sort((b).begin(), (b).end(), greater<long long>());
  int ans = 0;
  for (int i = 0; i < (n); i++) {
    if (b[i] <= max_a) break;
    h -= b[i];
    ans++;
  }
  while (h > 0) {
    h -= max_a;
    ans++;
  }
  cout << ans << endl;
  return 0;
}
