#include<iostream>
#include<cmath>
#include<algorithm>
using namespace std;

int main(){
  long N,H;
  cin >> N >> H;
  long a[N],b[N];
  for(int i=0;i<N;++i){
    cin >> a[i] >> b[i];
  }
  sort(a,a+N,greater<int>());
  sort(b,b+N,greater<int>());
  long sum=0,cnt=0;
  int max=a[0];
  for(int i=0;max<b[i];++i){
    sum+=b[i];
    ++cnt;
    if(sum>=H) break;
  }
  if(sum<H){
    cnt+=(int)ceil((double)(H-sum)/max);
  }
  cout << cnt << endl;
  return 0;
}
