"""

https://yukicoder.me/problems/no/1717

すぐに0だけになる？

"""


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

while len(A) >= 2:

    B = []

    for i in range(len(A)-2):

        tup = (A[i],A[i+1],A[i+2])

        if tup in ( (0,1,2),(1,2,0),(2,0,1) ):
            B.append(1)
        elif tup in ( (2,1,0),(1,0,2),(0,2,1) ):
            B.append(2)
        else:
            B.append(0)

    if sum(B) == 0:
        B = [0]
    A = B

print (A[0])