hhh <(︶︿︶)>_╭∩╮╭∩╮

#include <bits/stdc++.h>
#define int long long 
using namespace std;
int n1,n2,n3;
signed main(){ 
	cin>>n1>>n2>>n3;
	cout<<1.0*n1*0.2+1.0*n2*0.3+1.0*n3*0.5;
	return 0;
}