#!/usr/bin/perl -w
use strict;
use Socket;
while(<STDIN>) {
    s/\s+//g;
    chomp;
    my $iaddr = inet_aton("$_"); 
    if ( defined $iaddr ) {
        my $name  = gethostbyaddr($iaddr, AF_INET);
        if ( defined $name ) {
            print "$name\n"
        }
        else {
            print "No reverse for $_\n";
        }
    }
    else {
        print "No reverse for $_\n";
    }
}