#include <bits/stdc++.h>
using namespace std;
static const int max_size = 100000;
long long a[max_size];
long long b[max_size];
int main() {
  long long N, H;
  cin >> N >> H;
  for (long long i = 0; i < N; i++) {
    cin >> a[i] >> b[i];
  }
  sort(a, a + N);
  sort(b, b + N);
  long long a_max = a[N - 1];
  long long count = 0;
  for (long long i = 0; i < N; i++) {
    if (a_max <= b[i]) {
      H -= b[i];
      count++;
    }
  }
  count += (H / a_max);
  if ((H % a_max) > 0) {
    count++;
  }
  cout << count << endl;
  return 0;
}
