#include<bits/stdc++.h>
using namespace std;
int main(){
    float x,y,z,j,h,g,w;
    cin>>x>>y>>z;
    j=x*8.5;
    h=y*5.6;
    g=z*6.2;
    w=j+h+g;
    printf("%.1f",w);
}
/**************************************************************
	Problem: 1610
	User: huanglingkai
	Language: C++
	Result: Accepted
	Time:10 ms
	Memory:2072 kb
****************************************************************/