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

#include  <ext/pb_ds/assoc_container.hpp>
#include  <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;

template<class T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define pb push_back
#define x first
#define y second
#define FOR(i, a, b) for(int i = (a); i < (b); i++)
#define RFOR(i, a, b) for(int i = (a) - 1; i >= (b); i--)

typedef long long ll;
typedef double db;
typedef long double LD;
typedef pair<int, int> pii;
typedef pair<db, db> pdd;
typedef pair<ll, ll> pll;

string ask(string num)
{
	cout << num << endl;
	string resp;
	cin >> resp;
	return resp;
}

int solve(int b)
{	
	string al = "";
	for (char ch = '0'; ch <= '9'; ch++)
		al += ch;
	for (char ch = 'A'; ch <= 'Z'; ch++)
		al += ch;
	for (char ch = 'a'; ch <= 'z'; ch++)
		al += ch;
	
	//int m = sz(al);
	int d;
	cin >> d;
	vector<int> mxs(d, b);
	vector<int> mns(d, -1);
	string str = "";
	FOR (i, 0, d)
	{
		int mid = (mxs[i] + mns[i]) / 2;
		str += al[mid];
	}
	string resp = ask(str);
	if (resp == "correct")
	{
		return 0;
	}
	assert(sz(resp) == d);
	FOR (i, 0, d)
	{
		int mn = mns[i], mx = mxs[i];
		int mid = (mn + mx) / 2;
		
		if (mxs[i] < mid || mns[i] > mid)
		{
			cout << "cheater\n";
			return 0;
		}
		
		if (resp[i] == '=')
		{
			mns[i] = mxs[i] = mid;
		}
		else if (resp[i] == '+')
		{
			
			mns[i] = mid;
		}
		else if (resp[i] == '-')
		{
			
			mxs[i] = mid;
		}
		else
			assert(false);
	}
	
	
	return 0;
}

int32_t main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	
	int TET = 1e9;
	int b;
	cin >> b >> TET;
	for (int i = 1; i <= TET; i++)
	{
		if (solve(b))
		{
			break;
		}
		#ifdef ONPC
			cerr << "_____________________________\n";
		#endif
	}
	#ifdef ONPC
		cerr << "\nfinished in " << clock() * 1.0 / CLOCKS_PER_SEC << " sec\n";
	#endif
	return 0;
}