// (⁠◕⁠ᴗ⁠◕⁠✿⁠)

#include <bits/stdc++.h>
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define srep(i, s, n) for (ll i = s; i < (n); i++)
#define len(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
using namespace std;
template<typename T> using vc = vector<T>;
template<typename T> using vv = vc<vc<T>>;
template<typename T> using vvv = vv<vc<T>>;
using vi = vc<int>;using vvi = vv<int>; using vvvi = vv<vi>;
using ll = long long;using vl = vc<ll>;using vvl = vv<ll>; using vvvl = vv<vl>;
using ld = long double; using vld = vc<ld>; using vvld = vc<vld>; using vvvld = vc<vvld>;
using uint = unsigned int;
using ull = unsigned long long;
const ld pi = acos(-1.0);
const int inf = 0x3f3f3f3f;
const ll INF = 0x3f3f3f3f3f3f3f3f;
// const ll mod = 1000000007;
const ll mod = 998244353;
inline bool inside(ll y, ll x, ll H, ll W) {return 0 <= (y) and (y) < (H) and 0 <= (x) and (x) < (W); }

#define debug(var)  do{std::cout << #var << " : \n";view(var);}while(0)
template<typename T> void view(T e){cout << e << endl;}
template<typename T> void view(const vc<T>& v){for(const auto& e : v){ cout << e << " "; } cout << endl;}
template<typename T> void view(const vv<T>& vv){ for(const auto& v : vv){ view(v); } }


unsigned int randxor(){
    static unsigned int x = 123456789, y = 362436069, z = 521288629, w = 88675123;
    unsigned int t;
    t = (x ^ (x << 11)); x = y; y = z; z = w; return w = (w ^ (w >> 19)) ^ (t ^ (t >> 8));
}
int randint(int a, int b) {return(a + randxor() % (b - a));}

int main(){
    int N; cin >> N;
    string ans = ""; rep(i, N) ans += 'a';
    int K;
    cout << "? " << ans << endl;
    cin >> K;
    vi C(25); rep(i, 25) C[i] = i + 1;
    rep(t, N){
        rep(i, 25){
            int x = randint(0, 25), y = randint(0, 25);
            swap(C[x], C[y]);
        }
        rep(i, 25){
            int nk;
            ans[t] = C[i] + 'a';
            cout << "? " << ans << endl;
            cin >> nk;
            if (nk > K){
                K = nk;
                break;
            }
            if (nk < K){
                ans[t] = 'a';
                break;
            }
        }
    }
    cout << "! " << ans << endl;
}