#include<bits/stdc++.h>
using namespace std;
 int main(){
    int a,b,c,d;
    cin>>a>>b>>c;
    d=(a*0.20)+(b*0.30)+(c*0.50);
    cout<<d;
    return 0;
 } 
/**************************************************************
	Problem: 1565
	User: binzicheng1
	Language: C++
	Result: Accepted
	Time:35 ms
	Memory:2072 kb
****************************************************************/