#include <bits/stdc++.h>
using namespace std;
signed main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int N, H, a[100000], b[100000];
  cin >> N >> H;
  int amax = -1, sum = 0;
  for (int i = 0; i < (N); ++i) {
    cin >> a[i] >> b[i];
    amax = max(amax, a[i]);
  }
  int ans = 0;
  for (int i = 0; i < (N); ++i) {
    if (b[i] > amax) {
      sum += b[i];
      ans++;
    }
  }
  H -= sum;
  ans += (H + amax - 1) / amax;
  cout << ans << '\n';
  return 0;
}
