using System;

public class Program

{

    public static void Main()

    {

        int[]arr=new int []{5,7,3,8,9,5};

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

        summary(arr,index);

        Console.WriteLine(summary(arr,index));

    }

    public static  int summary (int[]arr,int index)

    {

        int x,sum=0 ;

        for (int i =0;i<arr.Length;i++)

        {

            x=i;

            if(x<index)

                sum+=arr[i];

        }

        return sum;

    }

    }

​