n = int(input())
A = list(map(int,input().split()))
for i in range(2*n-1):

    x,y,z = A[i],A[i+1],A[i+2]
    if (x,y,z) in ((0,1,2),(1,2,0),(2,0,1)):
        A[i] = 1
    elif (x,y,z) in ((0,2,1),(2,1,0),(1,0,2)):
        A[i] = 2
    else:
        A[i] = 0
n -= 1
if n%2:
    one = [2,0,1,0]*(n//2)+[2,0,1]
    two = [1,0,2,0]*(n//2)+[1,0,2]

else:
    one = [1,0,2,0]*(n//2)+[1]
    two = [2,0,1,0]*(n//2)+[2]

if A[:-2] == one:
    print(1)
elif A[:-2] == two:
    print(2)
else:
    print(0)