7.Odd_Occurrences

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

namespace _7.Odd_Occurrences
{
    class Program
    {
        static void Main(string[] args)
        {
            var text = Console.ReadLine().ToLower();
            var words = text.Split(' ');
            var counts = new Dictionary<string, int>();
            foreach (var w in words)
            {
                if (counts.ContainsKey(w)) counts[w]++;
                else counts[w] = 2;
            }

            var list = new List<string>();
            foreach (var pair in counts)
            {
                if (pair.Value % 2 !=0)
                {
                    list.Add(pair.Key);
                }
            }
            Console.WriteLine(string.Join(", ",list));
        }
    }
}