tall = [0, 0, 3, 4, 0, 5, 0, 0, 0]
tall = [4, 5, 0, 0, 0, 0]

while len(tall) > 0 and tall[0] == 0:
    tall.pop(0)

while tall and tall[-1] == 0:
    tall.pop()

print(tall)