using System;

using System.Collections.Generic;

public class Program

{

    public static bool IsIsomorphicStrings(string S, string T) 

    {

       if (S.Length != T.Length)

            return false;

​

        var map1 = new Dictionary<char, char>();

        var map2 = new Dictionary<char, char>();

​

        for (int i = 0; i < S.Length; i++)

        {

            char c1 = S[i];

            char c2 = T[i];

​

            if (map1.ContainsKey(c1)) 

            {

                if (c2 != map1[c1])

                    return false;

            } 

            else

            {

                if (map2.ContainsKey(c2))

                    return false;

​

                map1[c1] = c2;

                map2[c2] = c1;

            }

        }

​

        return true;

    }

    public static void Main()

    {

        Console.WriteLine("UniLecs");

        // Tests

        Console.WriteLine(IsIsomorphicStrings("egg", "add").ToString()); // true

        Console.WriteLine(IsIsomorphicStrings("foo", "bar").ToString()); // false

    }

}