#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, h;
  cin >> n >> h;
  int a[n], b[n];
  for (int i = 0; i < n; i++) cin >> a[i] >> b[i];
  pair<int, int> P[n];
  for (int i = 0; i < n; i++) {
    P[i].first = a[i];
    P[i].second = b[i];
  }
  sort(P, P + n);
  int ans = 0;
  for (int i = 0; i < n; i++) {
    if (P[n - 1].first < P[i].second) {
      h -= P[i].second;
      ans++;
    }
  }
  cout << ans + (h + P[n - 1].first - 1) / P[n - 1].first << endl;
}
