CountNumbers

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SquareNumbers
{
    class CountNumberts
    {
        static void Main()
        {
            List<int> nums = Console.ReadLine().Split(' ').Select(int.Parse).ToList();
            int[] countNums = new int[1001];
            foreach(int n in nums)
            {
                countNums[n]++;
            }
            for (int i = 0; i < countNums.Length; i++)
            {
                if(countNums[i] > 0)
                {
                    Console.WriteLine("{0} -> {1}",i,countNums[i]);
                }
            }

        }
    }
}