my $re = <STDIN>;
chomp ($re);
my $line = <STDIN>;
chomp ($line);
print "$line =~ /$re/\n";
if ( $line =~ /$re/ ) {
  print "match";
}
else {
  print "no match";
}

##</code><code>##

a\d3
a23

##</code><code>##

a23 =~ /a\d3/
match