#include <bits/stdc++.h>
//#include <atcoder/all>
using namespace std;
//using namespace atcoder;
//using mint = modint1000000007;
//const int mod = 1000000007;
//using mint = modint998244353;
//const int mod = 998244353;
//const int INF = 1e9;
//const long long LINF = 1e18;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i,l,r)for(int i=(l);i<(r);++i)
#define rrep(i, n) for (int i = (n) - 1; i >= 0; --i)
#define rrep2(i,l,r)for(int i=(r) - 1;i>=(l);--i)
#define all(x) (x).begin(),(x).end()
#define allR(x) (x).rbegin(),(x).rend()
#define P pair<int,int>
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }
int test(string s) {
	string t = "oiuytb";
	int ret = 0;
	rep(i, s.size())if (s[i] == t[i])ret++;
	return ret;
}
auto query(string s) {
	std::cout << "? " << s << endl;
	//return test(s);
	int n; cin >> n;
	return n;
}
void answer(string s) {
	std::cout << "! " << s << endl;;
	fflush(stdout);
}
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int n; cin >> n;
	string s, ans;
	rep(i, n) s += 'a';
	rep(i, n) ans += 'z';
	rep(i, n) {
		set<int>st;
		int pre = -1;
		rep(j, 25) {
			s[i] = 'a' + j;
			int x = query(s);
			if (x > pre) {
				pre = x;
				ans[i] = s[i];
			}
			st.insert(x);
		}
		if (1 == st.size())ans[i] = 'z';
	}
	answer(ans);
	return 0;
}