LambdaLinq 01 proba

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

namespace MultiDictionaries
{
    class Program
    {
        static void Main()
        {
            Dictionary<string, string> storePairs = new Dictionary<string, string>();
            string[] words = Console.ReadLine().Split(new char[] { ' ', '->' }, StringSplitOptions.RemoveEmptyEntries);

            while(words[0] != "end")
            {
                string keyInput = words[0];
                string valueInput = words[1];
                storePairs.Add(keyInput, valueInput);
            }

            string nullWord = "null";
            string defaultWord = Console.ReadLine();

            foreach (KeyValuePair<string, string> pair in storePairs)
            {
                if (storePairs.ContainsValue(nullWord))
                {
                    storePairs[pair.Key] = defaultWord;
                }
            }

            foreach()
        }
    }
}