#define _USE_MATH_DEFINES
 
#include <iostream>
#include <iomanip>
#include <sstream>
 
#include <algorithm>
#include <cmath>
 
#include <string>
#include <queue>
#include <vector>
#include <complex>
#include <set>
#include <map>
#include <stack>
#include <list>

#include <valarray>

#include<cassert>//assert();
//#include <random>//xAOJ
/////////
#define REP(i, x, n) for(int i = x; i < n; i++)
#define rep(i,n) REP(i,0,n)
#define P(p) cout<<(p)<<endl;
 
#define PII pair<int,int>
/////////
typedef long long LL;
typedef long double LD;
typedef unsigned long long ULL;
/////////
using namespace::std;
/////////
/////////

void solve(){
	string ans = "abcdefghij";
	string A,B;
	int num;
	string re;
	for(int i=0;i<10;++i){
		for(int j=0;j<10;++j){
			for(int k=0;k<10;++k){
				if(i==k){
					cout << j;
				}else{
					cout << 'a';
				}
			}cout << endl;
			cin >> num >> re;
			if( num ){
				ans[i] = (char)('0' + j);
				break;
			}
		}
	}
	cout << ans << endl;
}
int main(void){
    std::cin.tie(0); 
    std::ios::sync_with_stdio(false);
    std::cout << std::fixed;//
    //cout << setprecision(16);//
	
	//cpp
	solve();
	return 0;
}