#include <bits/stdc++.h>
using namespace std;
#define int long long
int a, b, c;//a就是作业成绩，b是小测成绩，c是期末考试成绩 
signed main()
{
	cin >> a >> b >> c; 
	double zuoye = a * (20 * 1.0 / 100);//20/100即20% 
	double xiaoce = b * (30 * 1.0 / 100);//30/100即30% 
	double qimo = c * (50 * 1.0 / 100);//50/100即50% 
	cout << zuoye + xiaoce + qimo << "\n";//输出他们的和 
	return 0;
}