#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 + *itr <= h && *itr > a[0]) {
    sum = sum + *itr;
    itr++;
    count++;
  }
  if ((h - sum) % a[0] == 0)
    count = count + ((h - sum) / a[0]);
  else
    count = count + ((h - sum) / a[0]) + 1;
  cout << count << endl;
  return 0;
}
