#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
#include <atcoder/dsu>
#include <atcoder/segtree>
using namespace atcoder;
using namespace std;
typedef long long ll;
typedef pair<ll,ll> pi;
#define ALL(x) x.begin(),x.end()
#define rep(i,a,b) for(int i=a;i<b;i++)
#define BS(A,x) binary_search(ALL(A),x)
#define LB(A,x) (ll)(lower_bound(ALL(A),x)-A.begin())
#define UB(A,x) (ll)(upper_bound(ALL(A),x)-A.begin())
#define COU(A,x) (UB(A,x)-LB(A,x))
using vi = vector<int>; 
using vvi = vector<vi>; 
using li =vector<ll>;
using lli=vector<li>;
using si =vector<char>;
using ssi =vector<si>;
const long long INF = 1e18;
const long long MOD=1e9+7;
//for (auto [key, val] : mp)
int main() { int n;cin>>n;string ans="";
vector<string>vec(n);
map<string,int>mp;
map<int,string>MP;
mp["a"]=0;
mp["b"]=1;
mp["c"]=2;
mp["e"]=4;
mp["d"]=3;
mp["f"]=5;
mp["g"]=6;
mp["h"]=7;
mp["i"]=8;
mp["j"]=9;
mp["k"]=10;
mp["l"]=11;
mp["m"]=12;
mp["n"]=13;
mp["o"]=14;
mp["p"]=15;
mp["q"]=16;
mp["r"]=17;
mp["s"]=18;
mp["t"]=19;
mp["u"]=20;
mp["v"]=21;
mp["w"]=22;
mp["x"]=23;
mp["y"]=24;
mp["z"]=25;
for(auto[a,b]:mp)MP[b]=a;
rep(i,0,n)vec[i]="a";
	rep(i,0,n){string ch="";
	rep(j,0,n)ch+=vec[j];
	cout<<"? "<<ch<<endl;
	int a;cin>>a;
	rep(j,1,26){ch="";
			rep(k,0,n){if(k!=i)ch+=vec[k];
			else ch+=MP[j];}
			cout<<"? "<<ch<<endl;
			int b;cin>>b;
			if(b>a){vec[i]=MP[j];break;}
			else if(b<a)break;
			else if(j==25)vec[i]="z";
		}
	}
	rep(i,0,n)ans+=vec[i];
	cout<<"! "<<ans<<endl;
}