Most Frequent Number / Array

using System;
using System.Linq;

namespace test
{
    class MainClass
    {
        public static void Main()
        {
            int[] arr = Console.ReadLine()
                                 .Split(' ')
                                   .Select(int.Parse).ToArray();

            var counters = new int[arr.Length];
            var counterMax = 0;
            var number = 0;

            for (int i = 0; i < arr.Length; i++)
            {
                for (int j = i; j < arr.Length; j++)
                {
                    if (arr[i] == arr[j])
                    {
                        counters[i]++;

                        if (counterMax < counters[i])
                        {
                            counterMax = counters[i];
                            number     = arr[i];
                        }
                    }
                }
            }

            Console.WriteLine(number);
        }
    }
}