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