def LeviCivitaSymbol(a, b, c):
    if len({a, b, c}) < 3:
        return 0
    else:
        return (b - a) % 3

N = int(input())
As = list(map(int, input().split()))

As = [LeviCivitaSymbol(As[i], As[i + 1], As[i + 2]) for i in range(2 * N - 1)]

one = ([1, 0, 2, 0] * (len(As) // 4 + 1))[len(As)-1::-1]
two = ([2, 0, 1, 0] * (len(As) // 4 + 1))[len(As)-1::-1]

if As == one:
    print(1)
elif As == two:
    print(2)
else:
    print(0)