#include <bits/stdc++.h>
using namespace std;
struct edge {
  long long to, cost;
};
long long ans, ans2;
long long n, h, a[111111], b[111111];
signed main() {
  cin >> n >> h;
  for (long long i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
  }
  long long max = 0, max2;
  for (long long i = 0; i < n; i++) {
    if (max < a[i]) {
      max = a[i];
      max2 = b[i];
    }
  }
  vector<long long> v;
  for (long long i = 0; i < n; i++) {
    if (max > b[i]) continue;
    h -= b[i];
    ans++;
    if (h <= 0) {
      cout << ans << endl;
      return 0;
    }
  }
  ans += h / max + 1;
  if (h % max == 0) ans--;
  cout << ans << endl;
  ;
}
