#include <bits/stdc++.h>
using namespace std;
long long const INF = 1LL << 60;
int main() {
  long long N, H;
  cin >> N >> H;
  vector<long long> a(N), b(N);
  for (int i = 0; i < N; i++) {
    cin >> a[i] >> b[i];
  }
  sort(a.rbegin(), a.rend());
  sort(b.rbegin(), b.rend());
  long long sum_b = 0;
  long long ans = 0;
  for (int i = 0; i < N; i++) {
    if (a[0] < b[i]) {
      sum_b += b[i];
      ans++;
    }
  }
  if (H <= sum_b) {
    cout << ans << endl;
    return 0;
  }
  H -= sum_b;
  if (H % a[0] == 0) {
    ans += H / a[0];
  } else {
    ans += H / a[0] + 1;
  }
  cout << ans << endl;
  return 0;
}
