cs arr j08 Subset Of Sum S _SORT ARRAY

/*
We are given an array of longegers and a number S. Write a program to find
if there exists a subset of the elements of the array that has a sum S.
 */
using System;
public class SubsetOfSumS
{
    public static void Main()
    {
        long n = long.Parse(Console.ReadLine()), c = 0;
        long sum = 0;//long n = 14, c = 0, sum = 0;//

        string[] str = Console.ReadLine().Split(' ');
        long[] ar = new long[str.Length];
        for (long i = 0; i < str.Length; i++)
            ar[i] = Convert.ToInt64(str[i]);
        // long[] ar = {2, 1, 2, 4, 3, 0, 9, 6};//8

        // Array.Sort(ar);
        for (long i = ar.Length - 1; i >= 0; i--)
        {
            sum = 0;
            for (long j = 0; j < ar.Length; j++)
            {
                if (i != j)
                {
                    sum = sum + ar[j];
                    if (sum == n)
                    {
                        Console.WriteLine("yes"); c++; break;
                    }
                    if (sum > n)
                        sum = sum - ar[j];
                }
            }
            if (c == 1) break;
        }
        if (c == 0)
            Console.WriteLine("no");
    }
}