#include<bits/stdc++.h>
using namespace std;
 
int n, h, a, b[100005], amax, cnt;

int main(){
  scanf("%d%d", &n, &h);
  for(int i = 0; i < n; i++){
    scanf("%d%d", &a, &b[i]);
    if(amax < a) amax = a;
  }
  sort(b,b+n, greater<int>());
  for(int i = 0; h > 0 && i < n && b[i] >= amax; cnt++, h-=b[i], i++);
  
  if(h > 0) cnt += (h-1)/amax + 1;
  printf("%d\n", cnt);
}
