#include<bits/stdc++.h> 
using namespace std;
float n,q,s,p;
int main()
     cin>>n>>q>>s;
     p=n*8.5+q*5.6+s*6.2;
     printf(%.1f,p)
}
/**************************************************************
	Problem: 1610
	User: chenyichuen
	Language: C++
	Result: Compile Error
****************************************************************/