using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine(sum());

    }

    static int sum()

    {

        int[] note = new int[4] {2, 3, 4, 5};

        int suma = 0;

        foreach (int element in note)

        {

            if (element <= 10 & element >= 0)

                suma = suma + element;

            /*else    

                return -1; */

        }

        return suma; // This was missing

    }

​

}