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

using namespace std;
using ll = long long;

constexpr int iINF = 1'000'000'000;
constexpr ll llINF = 1'000'000'000'000'000'000;

void solve (int N) {
    // AAA..Aを送り付ける
    // BAA..Aを送り付ける
    // ABA..Aを送り付ける
    // -> N回でAの場所を特定できる。
    // というわけで、A~Yまでを2500回以内で特定できて、ハッピーというわけです。

    vector<vector<int>> idx(26);

    map<int, bool> found;
    random_device rd;
    vector<bool> used(26, false);

    for (int _ = 0; _ < 25; _++) {
        // らんたくしましょ。そうしましょ。
        int i = 0;
        while (true) {
            i = rd() % 26;
            if (!used[i]) {
                used[i] = true;
                break;
            }
        }

        {
            vector<char> S(N, (char)(i + 'a'));
            cout << "? ";
            for (auto c : S) cout << c;
            cout << endl;
        }
        int normal; cin >> normal;

        if (normal == N) {
            for (int j = 0; j < N; j++) {
                found[j] = true;
                idx[i].push_back(j);
            }
            continue;
        }

        for (int j = 0; j < N; j++) {
            // 回数節約
            if (found.find(j) != found.end()) continue;

            vector<char> S(N, (char)(i + 'a'));
            S[j] = (char) (i + 'a' + 1);
            cout << "? ";
            for (auto c : S) cout << c;
            cout << endl;

            int res; cin >> res;
            if (res < normal) {
                idx[i].push_back(j);
                found[j] = true;
            }
        }
    }

    vector<char> ans(N, '_');
    for (int i = 0; i < 26; i++) {
        for (auto j : idx[i]) ans[j] = (char) (i + 'a');
    }

    char unused = 'a';
    for (int i = 0; i < 26; i++) if (!used[i]) unused = (char) ('a' + i);

    for (int i = 0; i < N; i++) if (ans[i] == '_') ans[i] = unused;

    cout << "! ";
    for (auto c : ans) cout << c;
    cout << endl;
}

int main () {
    int N; cin >> N;
    solve(N);
}