#!/afs/athena/contrib/perl/p
$prev = 'Hello';
print(">>");
while(<>){
    split;
    for $word (@_){
	if($known{$word}){
	    print $known{$word};
	}
	else{
	    $known{$word}=$prev;
	    print $word;
	}
	$prev=$word;
	print(" ");
    }
    print("\n>>");
}