#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, h;
  cin >> n >> h;
  vector<int> a(n), b(n);
  int a_max = 0;
  for (int i = 0; i < (n); ++i) {
    cin >> a[i] >> b[i];
    if (a_max < a[i]) a_max = a[i];
  }
  sort(b.begin(), b.end());
  int p = upper_bound(b.begin(), b.end(), a_max) - b.begin();
  long long b_sum = 0;
  for (int i = p; i < n; i++) {
    b_sum += b[i];
  }
  long long ans = 0;
  ans += (h - b_sum + a_max - 1) / a_max;
  ans += n - p;
  cout << ans << endl;
  return 0;
}
