string rearrangeWord (string word) {
    bool f = true;
    vector <char> v;
    for (int i = 0; i < word.length(); ++i)
        v.push_back(word[i]);
    f = std::next_permutation(v.begin(), v.end());
    if (!f) {
        return "no answer";
    }
    for (int i = 0; i < word.length(); ++i){
        word[i] = v[i];
    }
    return word;
}