#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  long long n, h;
  cin >> n >> h;
  int a[n];
  long long sum = 0;
  int b[n];
  int pr = -1;
  for (int(i) = (int)(0); (i) < (int)(n); ++(i)) {
    cin >> a[i] >> b[i];
    pr = max(a[i], pr);
  }
  long long at = 0;
  for (int(i) = (int)(0); (i) < (int)(n); ++(i)) {
    if (sum >= h) {
      cout << at;
      return 0;
    }
    if (b[i] > pr) {
      sum += b[i];
      at++;
    }
  }
  long long ans = ceil((h - sum) / (double)pr) + at;
  cout << ans;
}
