#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  long long 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());
  int ans = 0;
  for (int i = n - 1; i >= 0 && h > 0; i--) {
    if (b[i] >= max_a) {
      h -= b[i];
      ans++;
    }
  }
  ans += (h + max_a - 1) / max_a;
  cout << ans << endl;
}
