#include <iostream>
#include<string>
#include<cstdio>
#include<algorithm>
using namespace std;
int main(void){
   int a[100001]={},b[100002]={},n,h;
   int cnt=0,sum=0,i;
   cin>>n>>h;
   for(i=0;i<n;i++){
       cin>>a[i]>>b[i];
       if(a[0]<a[i])a[0]=a[i];
   }
   sort(b,b+i,greater<int>());
   while(1){
       if(b[k]>=a[0]){sum+=b[k];cnt++;}
       else break;
       if(sum>=h)break;
   }
   if(h-sum>0)cnt+=(h-sum)/a[0];
   if((h-sum)%a[0]!=0)cnt++;
   cout<<k<<endl;
   return 0;
}
