n = int(input())
A = list(map(int,input().split()))
for i in range(n):
    flag = 0
    for j in range(2*(n-1-i)+1):
        x,y,z = A[j],A[j+1],A[j+2]
        if (x==0 and y == 1 and z == 2) or (x==1 and y == 2 and z == 0) or (x==2 and y == 0 and z == 1):
            A[j] = 1
            flag = 1

        elif (x==0 and y == 2 and z == 1) or (x==2 and y == 1 and z == 0) or (x==1 and y == 0 and z == 2):
            A[j] = 2
            flag = 1

        else:
            A[j] = 0
    if flag == 0:
        print(0)
        exit()
print(A[0])