#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, h;
  cin >> n >> h;
  vector<int> a(n);
  vector<int> b(n);
  for (int i = 0; i < (n); ++i) cin >> a[i] >> b[i];
  sort(b.rbegin(), b.rend());
  long long ans = 0;
  int max = *max_element(a.begin(), a.end());
  for (int i = 0; h > 0 && i < n; ans++, i++) {
    h -= b[i];
  }
  for (; h > 0; ans++) {
    h -= max;
  }
  cout << ans << endl;
}
