#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, h;
  int a[100001] = {};
  int b[100001] = {};
  int a_max = 0;
  int count = 0;
  cin >> n >> h;
  for (int i = 0; i < n; i++) {
    int aa, bb;
    cin >> aa >> bb;
    a_max = aa > a_max ? aa : a_max;
    b[i] = bb;
  }
  for (int i = 0; i < n; i++) {
    if (b[i] > a_max) {
      h -= b[i];
      count++;
      if (h <= 0) {
        return (0);
      }
    }
  }
  count += h / a_max;
  if (h % a_max != 0) {
    count++;
  }
  cout << count << endl;
  return (0);
}
