#include <bits/stdc++.h>
using namespace std;
signed main() {
  long long n, h;
  cin >> n >> h;
  vector<long long> a(n), b(n);
  long long maxa = 0, ans = 0;
  for (long long i = 0; i < n; i++) {
    cin >> a.at(i) >> b.at(i);
    maxa = max(a.at(i), maxa);
  }
  for (long long i = 0; i < n; i++) {
    if (b.at(i) > maxa) {
      h -= b.at(i);
      ans++;
    }
    if (h <= 0) {
      cout << ans << endl;
      return 0;
    }
  }
  cout << ans + (h - 1) / maxa + 1 << endl;
}
