file = open('20A.txt')
n = int(file.readline())
kx = 0
ky = 0
k = 0
for i in range(n):
    x, y = map(int, file.readline().split())
    if x == 0:
        kx += 1
    elif y ==  0:
        ky += 1
    else:
        k += 1
print(k * kx * ky)