#include <bits/stdc++.h>
using namespace std;
const double PI = acos(-1);
const long long MOD = 1000000007;
int main() {
  int N, H;
  cin >> N >> H;
  vector<int> a(N), b(N);
  for (int i = 0; i < N; i++) cin >> a[i] >> b[i];
  sort(a.begin(), a.end());
  int amax = a[N - 1];
  sort(b.begin(), b.end());
  reverse(b.begin(), b.end());
  int count = 0;
  for (int i = 0; i < N; i++) {
    if (H > 0 && b[i] > amax) {
      H -= b[i];
      count++;
    }
  }
  count += ((H + amax - 1) / amax);
  cout << count << endl;
}
