#include<bits/stdc++.h>
using namespace std;

int main() {
    int N;
    cin>>N;
    string S="";
    for(int i=0;i<N;i++)S.push_back(rand()%26+'a');
    cout<<"? "<<S<<endl;
    int R;
    cin>>R;
    string AN="";
    for(int i=0;i<N;i++){
        set<char> D;
        D.insert(S[i]);
        bool OK=0;
        for(int k=0;k<25;k++){
            char c=S[i];
            while(D.count(c))c=rand()%26+'a';
            D.insert(c);
            string Q=S;
            Q[i]=c;
            cout<<"? "<<Q<<endl;
            int r;
            cin>>r;
            if(R<r){
                AN.push_back(c);
                OK=1;
                break;
            }
        }
        if(!OK)AN.push_back(S[i]);
    }
    cout<<"! "<<AN<<endl;
}