#include <bits/stdc++.h>
using namespace std;
const long long MAX_N = 100000, MAX_H = 1000000000;
int main(int argc, char const *argv[]) {
  long long N, H;
  cin >> N >> H;
  long long int a[MAX_N], b[MAX_N];
  for (long long i = 0; i < N; i++) cin >> a[i] >> b[i];
  sort(a, a + N, greater<long long int>());
  sort(b, b + N, greater<long long int>());
  long long int cnt = 0;
  for (size_t i = 0; i < N; i++) {
    if (b[i] < a[0])
      break;
    else {
      H -= b[i];
      cnt++;
    }
  }
  cnt += (H + (a[0] - 1)) / a[0];
  cout << cnt << endl;
  return 0;
}
