#include<bits/stdc++.h>
using namespace std;
int main(){
	int a,b,c,h;
	cin>>a>>b>>c;
	h=a*0.2+b*0.3+c*0.5;
	cout<<h<<endl;
}
/**************************************************************
	Problem: 1565
	User: xiaojingxuan
	Language: C++
	Result: Accepted
	Time:27 ms
	Memory:2072 kb
****************************************************************/