#include<bits/stdc++.h>
using namespace std;
 
int main(){
  int n, h, a, b, amax = 0, cnt = 0;
  priority_queue<int> pq;
  scanf("%d%d", &n, &h);
  for(int i = 0; i < n; i++){
    scanf("%d%d", &a, &b);
    if(amax < a) amax = a;
    pq.push(b);
  }
  while(h > 0 && !pq.empty()){
    b = pq.top(); pq.pop();
    if(b <= amax) break;
    h -= b;
    cnt++;
  }
  if(h > 0) cnt += (h-1)/amax + 1;
  printf("%d\n", cnt);
}
