dict-ref

using System;
using System.Collections.Generic;

class test
{
    static void Main()
    {
        string[] line = Console.ReadLine().Split();
        var dict = new Dictionary<string, int>();

        while (line[0] != "end")
        {
            string firstName = line[0];
            string secondPart = line[2];

            bool isNumber = int.TryParse(secondPart, out int num);

            if (isNumber)
            {
                dict[firstName] = num;
            }
            else
            {
                if (dict.ContainsKey(secondPart))
                {
                    dict[firstName] = dict[secondPart];
                }
            }

            line = Console.ReadLine().Split();
        }

        foreach (var item in dict)
        {
            Console.WriteLine($"{item.Key} === {item.Value}");
        }
    }
}