n = int(input())
a = list(map(int, input().split()))
b = [0] * (2 * n - 1)
for i in range(2 * n - 1):
    if (a[i] + 1) % 3 == a[i + 1] and (a[i + 1] + 1) % 3 == a[i + 2]:
        b[i] = 1
    elif (a[i] - 1) % 3 == a[i + 1] and (a[i + 1] - 1) % 3 == a[i + 2]:
        b[i] = 2
n -= 1
for i in range(n):
    if b[i * 2 + 1] != 0:
        print(0)
        exit(0)
    if b[i * 2] == 0 or b[i * 2 + 2] == 0 or b[i * 2] == b[i * 2 + 2]:
        print(0)
        exit(0)
else:
    if (b[0] == 1) ^ (n & 1):
        print(1)
    else:
        print(2)