哇，简单的

#include <bits/stdc++.h>
using namespace std;

int main(){
    int a, b, c;
    cin >> a >> b >> c;
    cout << (int)(a * 0.2 + b * 0.3 + c * 0.5);
    return 0;
}

#include <bits/stdc++.h>
using namespace std;
int main()
{
	int A,B,C;
	cin>>A>>B>>C;
	cout<<A*0.2+B*0.3+C*0.5<<endl;
	return 0;
}

#include<iostream>
#include<cstdio>
using namespace std;
int a,b,h,x;
int main()
{
    cin>>a>>b>>h;
    cout<<a/5+b/10*3+h/2;
    return 0;
}