#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#define _GLIBCXX_DEBUG
#include "algo/debug.h"
#else
#define debug(...) void(0)
#endif
using ll = long long;
using ld = long double;
const ll linf=(1LL<<60) - 1;
const int inf=(1LL<<30) - 1;
#define len(obj) int(obj.size())
#define overload4(a,b,c,d,name,...) name
#define overload5(a,b,c,d,e,name,...) name
#define rep1(n) for(long long _=0;_<n;++_)
#define rep2(i,n) for(long long i=0;i<n;++i)
#define rep3(i,a,b) for(long long i=a;i<b;++i)
#define rep4(i,a,b,c) for(long long i=a;i<b;i+=c)
#define rep(...) overload4(__VA_ARGS__,rep4,rep3,rep2,rep1)(__VA_ARGS__)
#define rrep1(n) for(ll _=n-1;_>=0;--_)
#define rrep2(i,n) for(ll i=n-1;i>=0;--i)
#define rrep3(i,a,b) for(ll i=b-1;i>=a;--i)
#define rrep4(i,a,b,c) for(ll i=(a)+((b)-(a)-1)/(c)*(c);i>=(a);i-=c)
#define rrep(...) overload4(__VA_ARGS__,rrep4,rrep3,rrep2,rrep1)(__VA_ARGS__)
#define each1(i,a) for(auto&&i:a)
#define each2(x,y,a) for(auto&&[x,y]:a)
#define each3(x,y,z,a) for(auto&&[x,y,z]:a)
#define each4(w,x,y,z,a) for(auto&&[w,x,y,z]:a)
#define each(...) overload5(__VA_ARGS__,each4,each3,each2,each1)(__VA_ARGS__)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend() 
#define vec(type,name,...) vector<type> name(__VA_ARGS__)
#define vv(type,name,h,...) vector name(h,vector<type>(__VA_ARGS__))
#define vvv(type,name,h,w,...) vector name(h,vector(w,vector<type>(__VA_ARGS__)))
#define vvvv(type, name, h, w, n, ...) vector<vector<vector<vector<type>>>> name(h, vector<vector<vector<type>>>(w, vector<vector<type>>(n, vector<type>(__VA_ARGS__))))
struct Setting{ Setting(){ cin.tie(nullptr)->sync_with_stdio(0); fixed(cout).precision(12); } }Setting;
//-----------------------------------
void query(string t) {
    cout << "? " << t << endl;
}

int main() {
    const int M = 2500;
    int N; cin >> N;
    string T = string(N, 'a'), ans = "";
    rep(i, N) {
        int mx = -1, mi = inf;
        char a;
        for(char s = 'a'; s <= 'y'; s++) {
            T[i] = s;
            query(T);
            int t; cin >> t;
            if(mx < t) {
                mx = t;
                a = s;
            }
            mi = min(mi, t);
        }
        if(mx == mi) a = 'z';
        ans += a;
    }
    cout << "! " << ans << endl;
}