VARIABLE 0 <= VARIABLE 0 POWER VARIABLE 0
VARIABLE 1 <= VARIABLE 0 + VARIABLE 0
VARIABLE 2 <= VARIABLE 1 * VARIABLE 1
OPEN z
FILE 0 <= VARIABLE 0 + VARIABLE 1
FILE 1 <= FILE 0 * VARIABLE 2
OPEN z1
FILE 0 <= VARIABLE 1 * VARIABLE 2
FILE 1 <= FILE 0 + VARIABLE 2