#include <bits/stdc++.h>
using namespace std;
int main(int argc, char const *argv[]) {
  int N;
  long long H;
  cin >> N >> H;
  vector<long long> a(N);
  vector<long long> b(N);
  long long a_max = 0;
  long long b_sum = 0;
  for (int i = 0; i < N; i++) {
    cin >> a[i] >> b[i];
    if (a_max < a[i]) {
      a_max = a[i];
    }
    b_sum += b[i];
  }
  long long ans = 0;
  if (b_sum >= H) {
    long long sum = 0;
    sort(b.begin(), b.end(), greater<long long>());
    for (int i = 0; i < N; i++) {
      sum += b[i];
      ans++;
      if (sum >= H) {
        break;
      }
    }
  } else {
    long long sum = 0;
    sort(b.begin(), b.end(), greater<long long>());
    for (int i = 0; i < N; i++) {
      if (b[i] < a_max) {
        break;
      }
      sum += b[i];
      ans++;
    }
    ans += ((H - sum) % a_max == 0 ? (H - sum) / a_max : (H - sum) / a_max + 1);
  }
  cout << ans << "\n";
  return 0;
}
