import sys
input = sys.stdin.readline
from time import time

time0=time()

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

X=[(0,1,2),(1,2,0),(2,0,1)]
Y=[(2,1,0),(1,0,2),(0,2,1)]

N=len(A)

while len(A)>1:
    B=[]
    for i in range(len(A)-2):
        C=(A[i],A[i+1],A[i+2])

        if C in X:
            B.append(1)
        elif C in Y:
            B.append(2)
        else:
            B.append(0)

    A=B

    if time()-time0>1.8:
        print(0)
        exit()

print(A[0])