#include <bits/stdc++.h>
using namespace std;
int main(void) {
  vector<long long int> b;
  vector<long long int> a;
  long long int t_a, t_b, n, h;
  cin >> n >> h;
  for (long long int i = 0; i < n; i++) {
    cin >> t_a >> t_b;
    a.push_back(t_a);
    b.push_back(t_b);
  }
  sort(a.begin(), a.end(), std::greater<long long int>());
  sort(b.begin(), b.end(), std::greater<long long int>());
  auto itr = b.begin();
  long long int sum = 0;
  long long int count = 0;
  while (sum < h) {
    if (*itr > a[0]) {
      sum = sum + *itr;
      itr++;
    } else {
      sum = sum + a[0];
    }
    count++;
  }
  cout << count << endl;
  return 0;
}
