#include <iostream>
#include <string>
#include <algorithm>
using namespace std; 
int n,hp,s[100010],t[100010],ans;  
int main()  
{ 
    cin>>n>>hp;
    for(int i=0;i<n;i++)cin>>s[i]>>t[i];
    sort(s,s+n,greater<int>());
    int max=s[0];
    sort(t,t+n,greater<int>());
    for(int i=0;i<n;i++)if(t[i]>max&&hp>0){hp-=t[i];ans++;}
    if(hp>0)ans+=(hp+max-1)/max;
    cout<<ans;
    return 0;
}