use strict;
use warnings;
use diagnostics;

while (<STDIN>) {
	chomp;
	if (/[0-9]{3}/) {
		
		print "\tIt Matches.\n";
	} else {
		print"\tIt doesn't match.\n";
	}
}


##</code><code>##

D:\perlscripts>perl test.pl
1
        It doesn't match.
12
        It doesn't match.
123
        It Matches.
12345
        It Matches.
1234567890
        It Matches.

D:\perlscripts>