#include <iostream> #include <vector> #include <string> #include <cstring> #include <math.h> #include <cmath> #include <limits.h> #include <map> #include <unordered_map> #include <set> #include <queue> #include <algorithm> #include <functional> #include <stdio.h> using namespace std; long long MOD = 1000000007; int N; void func( string s ) { if ( s.length() == 18 ) { return; } if ( N == 0 ) { return; } cout << "a" << s << "a" << endl; N--; for ( char c = 'a'; c <= 'z'; c++ ) { func( s+c ); } } int main() { cin >> N; string s; func(s); return 0; }