from itertools import *
def f(x, y, z, w):
    return (y <= x or z) and (z <= y)
table = [(1, 0, 0, 0), (1, 1, 0, 0), (1, 1, 0, 1), (0, 1, 1, 0)]
for p in permutations('wxyz'):
    if [f(**dict(zip(p, r))) for r in table] == [0, 0, 0, 0]:
        print(p)