use strict;

my $i = "mmmm9";
my $a = match_rtn( $i );
print $a, "\n";

$i = "mmm";
$a = match_rtn( $i );
print $a, "\n";

sub match_rtn {
    my $str = shift;

    $str =~ m/(\d+)/;
    return $1;   
}