#include<bits/stdc++.h> 
using namespace std;
	int main(){
	int x,y;
	float p;
	cin>>x>>y;
	
	p=5*(y/x);
	
	cout<<p;
	return 0;
  }
    






	

/**************************************************************
	Problem: 1417
	User: zhangchenhao
	Language: C++
	Result: Accepted
	Time:17 ms
	Memory:2072 kb
****************************************************************/