using System;

using System.Linq;

using System.Text.RegularExpressions;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var s1 = "my&friend&Paul has heavy hats! &";

        var s2 = "my friend John has many many friends &";

        s1 = Regex.Replace(s1, @"[^a-z]", ""); // only count lowercase chars 

        s2 = Regex.Replace(s2, @"[^a-z]", "");

        var freq1 = StringCharFrequency(s1);

        var freq2 = StringCharFrequency(s2);

        var keySet = new HashSet<char>(freq1.Keys); // all chars to add to new str

        keySet.UnionWith(freq2.Keys);

        var strings = new List<string>();

        int count1, count2;

        string tempS;

        foreach (var key in keySet)

        {

            if (!freq1.TryGetValue(key, out count1))

                count1 = 0;

            if (!freq2.TryGetValue(key, out count2))

                count2 = 0;

            if (count1 <= 1 && count2 <= 1) continue;

            tempS = string.Empty;

            if (count1 > count2) tempS  += $"1:{new string(key, count1)}";

            else if (count2 > count1) tempS += $"2:{new string(key, count2)}";

            else tempS += $"=:{new string(key, count1)}";

            strings.Add(tempS);

        }

        // len desc, alpha by group (1,2,=), then alpha

        var sortedStrings = strings.OrderByDescending(x => x.Length)

            .ThenBy(x => (int)x[0])

            .ThenBy(x => x[2])

            .ToList();

        Console.WriteLine(string.Join('/', sortedStrings));

    }

    private static Dictionary<char, int> StringCharFrequency(string s) 

    {

        var freq = new Dictionary<char, int>();

        foreach (var ch in s)

        {

            if (freq.ContainsKey(ch))

                freq[ch]++;

            else

                freq[ch] = 1;

        }

        return freq;

    }

}