#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: linyuhang
	Language: C++
	Result: Accepted
	Time:31 ms
	Memory:2072 kb
****************************************************************/