#!/usr/bin/perl -w

# John Kerl
# kerl.john.r@gmail.com
# 2006-05-26

$parity = 0;
while ($line = <>) {
    chomp $line;
    print $line;
    if ($parity) {
        print "\n";
    }
    else {
        print " ";
    }
    $parity = !$parity;
}
if ($parity) {
    print "\n";
}