from itertools import *
def f(x, y, z, w):
    return w and ((x <= y) == (y <= z))
for a in product([0, 1], repeat = 6):
    table = [(0, a[0], a[1], a[2]), (0, 0, a[3], 0), (0, a[4], a[5], 0)]
    if len(table) == len(set(table)):
        for p in permutations('xyzw'):
            if [f(**dict(zip(p, r))) for r in table] == [1, 1, 1]:
                print(p)