#include <bits/stdc++.h>
using namespace std;
const int a = 1e5;
int main() {
  long long n, h, ar[a], arr[a], cnt = 0, x, j;
  cin >> n >> h;
  for (int i = 0; i < n; i++) {
    cin >> ar[i] >> arr[i];
  }
  sort(arr, arr + n);
  sort(ar, ar + n);
  x = ar[n - 1];
  j = n - 1;
  while (arr[j] > x) {
    cnt++;
    h -= arr[j];
    j--;
  }
  while (h > 0) {
    h -= x;
    cnt++;
  }
  cout << cnt;
}
