#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,i,z,x=0;
	cin>>n>>i>>z;
		x=n*0.2+i*0.3+z*0.5;
    	cout<<x;
    }

/**************************************************************
	Problem: 1565
	User: huxuanchen
	Language: C++
	Result: Accepted
	Time:25 ms
	Memory:2072 kb
****************************************************************/