#include <iostream>
#include <map>
#include <vector>
#include <algorithm>

class Mix
{
public:
    struct all_in_one
    {
        int amount = 0;
        char letter;
        int number_of_string = 0;
    };

    static std::string mix(const std::string &s1, const std::string &s2)
    {
        //strings parsing
        std::map<char, int> letters1, letters2;

        for (int i = 0; i < 26; ++i)
        {
            letters1.emplace('a' + i, 0);
            letters2.emplace('a' + i, 0);
        }
        for (const auto item : s1)
            if (std::islower(item))
                letters1[item]++;

        for (const auto item : s2)
            if (std::islower(item))
                letters2[item]++;

        //split all data in to one vector
        std::vector<all_in_one> one_string;

        for ( char c = 'a'; c <= 'z'; ++c)
        {
            if (letters1[c] > 1 && letters1[c] > letters2[c])
                one_string.push_back({letters1[c], c , 1});
            if (letters2[c] > 1 && letters1[c] < letters2[c])
                one_string.push_back({letters2[c], c , 2});
            if (letters2[c] > 1 && letters1[c] == letters2[c])
                one_string.push_back({letters2[c], c , 3});
        }

        //sorting by amount (value) and by char together!!!
        std::sort(one_string.begin(), one_string.end(),
                  [](const all_in_one& first, const all_in_one& second) -> bool
                        {
                            if (first.amount > second.amount)
                                return true;
                            if (first.amount < second.amount)
                                return false;
                            if (first.letter == second.letter)
                                return false;
                            if (first.number_of_string != second.number_of_string)
                                return first.number_of_string < second.number_of_string;
                            return first.letter < second.letter;

                        });

        //just print small letters from s1 and s2 strings in one string
        std::string result = "";
        for (const auto& item : one_string)
        {
            std::string str(item.amount, item.letter);
            if (item.number_of_string == 1 or item.number_of_string == 2)
                result += std::to_string(item.number_of_string) + ":" + str + "/";
            else
            {
                result += "=:" + str + "/";
            }
        }
        if (result.size() > 0)
            result.pop_back();
        return result;
    };
};