#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int N_MAX = (100001);
ll a[N_MAX], b[N_MAX], N, H, amax, ct;
int main() {
  cin >> N >> H;
  for (int i = 0; i < N; i++) {
    cin >> a[i] >> b[i];
  }
  sort(a, a + N, greater<ll>());
  sort(b, b + N, greater<ll>());
  amax = a[0];
  ct = 0;
  for (int i = 0; ((b[i] > amax) && (H > 0)) && i < N; i++) {
    H -= b[i];
    ct++;
  }
  ct += ((H + amax - 1) / amax);
  cout << ct << endl;
  return 0;
}
