#include<bits/stdc++.h>
using namespace std;
int main(){
	float a,b,c,p;
	cin>>a>>b>>c;
	a=a*8.5,b=b*5.6,c=c*6.2;
	p=a+b+c;
	printf("%.1f",p);
	return 0;
} 
/**************************************************************
	Problem: 1610
	User: fuhoubin
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2072 kb
****************************************************************/