from itertools import *
def f(x, y, z, w):
    return (not(y)) and x and ((not(z)) or w)
table = [(0, 1, 0, 0), (1, 1, 0, 0), (1, 1, 1, 0)]
for p in permutations('wxyz'):
    if [f(**dict(zip(p, r))) for r in table] == [1, 1, 1]:
        print(p)