# include < iostream >
const int MAX_SETS = 10 ;
const int MAX_WORDS = 10 ;
const int MAX_WORD_LENGTH = 20 ;
void backtracking ( int level , int n, char sets [MAX_SETS][MAX_WORDS][MAX_WORD_LENGTH], char solution [MAX_SETS][MAX_WORD_LENGTH]) {
if ( level == n) {
for ( int i = 0 ; i < n; ++i) {
std :: cout << solution [i] << ' ' ;
}
std :: cout << std :: endl ;
return ;
}
for ( int i = 0 ; i < MAX_WORDS && sets [ level ][i][ 0 ] != '\0' ; ++i) {
for ( int j = 0 ; j < MAX_WORD_LENGTH; ++j) {
solution [ level ][j] = sets [ level ][i][j];
if ( sets [ level ][i][j] == '\0' ) break ;
}
backtracking ( level + 1 , n, sets , solution );
}
}
int main () {
int n;
std ::cin >> n;
char sets [MAX_SETS][MAX_WORDS][MAX_WORD_LENGTH] = { 0 };
for ( int i = 0 ; i < n; ++i) {
int nj ;
std ::cin >> nj ;
for ( int j = 0 ; j < nj ; ++j) {
std ::cin >> sets [i][j];
}
}
char solution [MAX_SETS][MAX_WORD_LENGTH] = { 0 };
backtracking ( 0 , n, sets , solution );
return 0 ;
}