#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, h;
  cin >> n >> h;
  vector<long long> a(n), b(n);
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
  }
  sort(a.begin(), a.end(), greater<long long>());
  sort(b.begin(), b.end(), greater<long long>());
  int total = 0, count = 0;
  for (int i = 0; b[i] > a[0] && i < n && h > 0; i++) {
    total += b[i];
    count++;
    h -= b[i];
  }
  count += (h + a[0] - 1) / a[0];
  cout << count << endl;
  return 0;
}
