Password Validation, Perl

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#perl 5.22.1

#    Write a Perl function that takes in a password and checks whether it's valid.  The password should follow the following rule:
#    Passwords must be at least 8 characters long.
#    Between 8-11: requires mixed case letters, numbers and symbols
#    Between 12-15: requires mixed case letters and numbers
#    Between 16-19: requires mixed case letters
#    20+: any characters desired
sub pwdChk{
    my ($pwd) = @_;
    my $len = length($pwd);
    print "\nlength = $len";
    my $ret = "invalid";
    if($len < 8){
        $ret = "invalid";
        }elsif($len < 12){
             if($pwd =~ /\d/ && $pwd =~ /[a-z]/ && $pwd =~ /[A-Z]/ && $pwd =~ /[^A-Za-z0-9]/){
                $ret = "valid";
            }
            }elsif($len < 16){
                if($pwd =~ /\d/ && $pwd =~ /[a-z]/ && $pwd =~ /[A-Z]/){
                    $ret = "valid";
                }
                }elsif($len < 20){
                    if($pwd =~ /[a-z]/ && $pwd =~ /[A-Z]/){
                        $ret = "valid";
                    }
                    }else{
                        $ret = "valid";
                    }
    return $ret;

}

my$pwd = <STDIN>;
my$res = pwdChk($pwd);
print "\n$pwd is $res";

[ - ] Show input
Absolute running time: 0.31 sec, cpu time: 0.23 sec, memory peak: 3 Mb, absolute service time: 0,32 sec