#!/usr/bin/perl

use strict;
use warnings;

for my $A (1..3) {
	for my $B (1..2) {
		for my $C (1..3) {
			
			print "$A$B$C\n";
			
		};
	};
};

__END__

= for output

111
112
113
121
122
123
211
212
213
221
222
223
311
312
313
321
322
323

=cut