#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: yangjunwen
	Language: C++
	Result: Accepted
	Time:6 ms
	Memory:2072 kb
****************************************************************/