using System;

public class Program

{

    public static int Sum(int []arr, int index)//14

    {

        if(index < 0)

        {

            return 0;

        }

        else

        {

            return Sum(arr, index -1) + arr[index];

        }   

    }

    public static void Main()

    {

        int []arr = new int[5]{1,2,3,4,5};

        Console.WriteLine(Sum(arr,1));

    }

}