#include<bits/stdc++.h>
using namespace std;
int main(){
	float a,b,c,h;
	cin>>a>>b>>c;
	h=a+b+c;
	if(h>=200){
		cout<<fixed<<setprecision(1)<<h*0.8;
	} else{
		cout<<fixed<<setprecision(1)<<h*0.9;
	}
}
/**************************************************************
	Problem: 1624
	User: linmiaoling
	Language: C++
	Result: Accepted
	Time:12 ms
	Memory:2072 kb
****************************************************************/