#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, h;
  cin >> n >> h;
  long long a[n + 1], b[n + 1];
  long long amax = 0;
  for (int i = 1; i <= n; i++) {
    cin >> a[i] >> b[i];
    amax = max(amax, a[i]);
  }
  sort(b + 1, b + n + 1);
  int tuyoi = lower_bound(b + 1, b + n + 1, amax) - b;
  long long count = 0;
  for (int i = tuyoi; i <= n; i++) {
    h -= b[i];
    count++;
  }
  count += ceil((h * 1.0) / amax);
  cout << count << endl;
  return 0;
}
