#include<bits/stdc++.h>
#define rep(i,j,k) for (int i=j;i<(k);++i)
#define all(i) (i).begin(),(i).end()
#define sz(i) (int)(i).size()
using namespace std;
typedef vector<int> vi;

vector<char> chars;

int b, n;

void solve() {
    int d;
    cin >> d;

    vi lows(d, 0);
    vi highs(d, b-1);
    vi guess(d, 0);

    while (true) {
        rep(i,0,d) {
            guess[i] = (lows[i] + highs[i])/2;
            cout << chars[guess[i]];
        }
        cout << endl;

        string res;
        cin >> res;

        if (!res.compare("correct")) return;

        rep(i,0,d) {
            if (res[i] == '-') {
                highs[i] = min(highs[i], guess[i]-1);
            }
            if (res[i] == '+') {
                lows[i] = max(lows[i], guess[i]+1);
            }
            if (res[i] == '=') {
                lows[i] = max(lows[i], guess[i]);
                highs[i] = min(highs[i], guess[i]);
            }

            if (highs[i] < lows[i]) {
                cout << "cheater" << endl;
                cin >> res;
                return;
            }
        }

        // break;
    }
}

int main() {
    for(char c='0';c<='9';++c) chars.push_back(c);
    for(char c='A';c<='Z';++c) chars.push_back(c);
    for(char c='a';c<='z';++c) chars.push_back(c);

    cin >> b >> n;

    while (n--) solve();

    return 0;
}