Product of 3 numbers

a = float(input())
b = float(input())
c = float(input())

if a == 0 or b == 0 or c == 0:
    sign = 'zero'
elif a < 0 and b < 0 and c < 0:
    sign = 'negative'
elif (a > 0 and b > 0 and c > 0) or (a < 0 and b < 0 and c > 0) or (a < 0 and b > 0 and c < 0) \
        or (a > 0 and b < 0 and c < 0):
    sign = 'positive'
print(sign)