using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var n = NN;
        var r = new Random();
        var init = new char[n];
        for (var i = 0; i < n; ++i) init[i] = (char)(r.Next(26) + 'a');
        var ix = Q(init);
        var ans = (char[]) init.Clone();
        for (var i = 0; i < n; ++i)
        {
            for (var j = 'a'; j <= 'z'; ++j)
            {
                if (j == init[i]) continue;
                var tmp = init[i];
                init[i] = j;
                var nx = Q(init);
                init[i] = tmp;
                if (nx < ix) break;
                if (nx > ix)
                {
                    ans[i] = j;
                    break;
                }
            }
        }
        WriteLine($"! {string.Concat(ans)}");
    }
    static int Q(char[] s)
    {
        WriteLine($"? {string.Concat(s)}");
        return NN;
    }
}