11. Equal Sums

using System;
using System.Linq;

namespace test
{
    class MainClass
    {
        public static void Main()
        {


            int[] arr = Console.ReadLine()
                                   .Split(' ')
                                       .Select(int.Parse)
                                           .ToArray();

            var number = 0;
            bool suchIndexExists = false;

            if (arr.Length == 1)
                suchIndexExists = true;


            for (int i = 0; i < arr.Length; i++)
            {
                var leftSum = 0;
                var rightSum = 0;

                for (int l = 0; l < i; l++)
                {
                    leftSum += arr[l];
                }

                for (int r = i + 1; r < arr.Length; r++)
                {
                    rightSum += arr[r];
                }

                if (leftSum == rightSum)
                {
                    suchIndexExists = true;
                    number = i ;
                }
            }

            if (suchIndexExists)
            {
                Console.WriteLine(number);
            }
            else
            {
                Console.WriteLine("no");
            }
        }
    }
}