using System;

public class Program

{

    public static void Main()

    {

int s;

int tp = 0;

 s=int.Parse(Console.ReadLine());

while(s>=0)

{

if(s % 2==0)

​

tp =( tp + s ) ;

s=int.Parse(Console.ReadLine());

​

​

}

Console.WriteLine(tp);

    }

}