有点难

#include<bits/stdc++.h>
using namespace std;
long long x;
long long y; 
int main(){
	cin>>x>>y;
	if(x+12000*2>=y){
		cout<<5;
	}else{
		if(x+18000*2>=y){
			cout<<6;
		}else{
			if(x+24000*2>=y){
				cout<<8;
			}else{
				if(x+36000*2>=y){
					cout<<11;
				}else{
					cout<<((y-x-1)/2/48000+1)*13;
				}
			}
		}
	}
	return 0;
}