#include<bits/stdc++.h>
using namespace std;
int main(){ 
	int a,b;
	double h;
	cin>>a>>b;
	h=b/a;
	cout<<5*h;
	
}


/**************************************************************
	Problem: 1417
	User: zhuangsongyu
	Language: C++
	Result: Accepted
	Time:12 ms
	Memory:2072 kb
****************************************************************/