func ack() {
	n = n+1
	if($1 == 0) return ($2+1)
	if($2 == 0) 	 return (ack($1 - 1, 1))
	return (ack($1 - 1, ack($1, $2 - 1)))
}
n=0
ack(3,3)
print n, "calls\n"