#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, h;
  cin >> n >> h;
  int b[n];
  int a_max = 0;
  for (int i = 0; i < n; i++) {
    int a;
    cin >> a >> b[i];
    if (a > a_max) a_max = a;
  }
  int count = 0;
  int b_sum = 0;
  for (int i = 0; i < n; i++) {
    if (b[i] > a_max) {
      b_sum += b[i];
      count++;
    }
  }
  count += (h - b_sum) / a_max;
  if ((h - b_sum) % a_max != 0 && (h - b_sum) / a_max != 0) count++;
  cout << count << endl;
  return 0;
}
