// "036.hac" -- should pass

// note: L2 has no direction specified, so may be send or receive, or both!
defproc sum_diff(chan?(int) L1; chan(int) L2; chan!(int) R) {
int x, z;
chp {
	L1?(x), L2?(z);
	R!(x-z), L2!(x+z)
}
}

