#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, h;
  cin >> n >> h;
  vector<pair<long long, long long> > A(n);
  for (long long i = 0; i < n; i++) cin >> A[i].first >> A[i].second;
  sort(A.rbegin(), A.rend());
  long long max_a = A[0].first;
  long long cnt = 0;
  long long sum = 0;
  for (auto &&p : A) {
    if (p.second > max_a) {
      cnt++;
      sum += p.second;
    }
  }
  h -= sum;
  if (h <= 0) {
    cout << cnt << endl;
    return 0;
  }
  cout << cnt + h / max_a + (h % max_a != 0) << endl;
  return 0;
}
