# 高速化愚直解　想定 TLE

import sys
input = sys.stdin.buffer.readline

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

bit_0 = int(''.join([str(int(e == 0)) for e in As]), 2)
bit_1 = int(''.join([str(int(e == 1)) for e in As]), 2)
bit_2 = int(''.join([str(int(e == 2)) for e in As]), 2)

for i in range(N):
    l = 2 * (N - i) - 1
    new_bit_1 = 0
    new_bit_1 |= bit_0 & (bit_2 >> 1) & (bit_1 >> 2)
    new_bit_1 |= bit_2 & (bit_1 >> 1) & (bit_0 >> 2)
    new_bit_1 |= bit_1 & (bit_0 >> 1) & (bit_2 >> 2)
    new_bit_2 = 0
    new_bit_2 |= bit_0 & (bit_1 >> 1) & (bit_2 >> 2)
    new_bit_2 |= bit_1 & (bit_2 >> 1) & (bit_0 >> 2)
    new_bit_2 |= bit_2 & (bit_0 >> 1) & (bit_1 >> 2)
    bit_1 = new_bit_1
    bit_2 = new_bit_2
    bit_0 = int('1' * l, 2) ^ bit_1 ^ bit_2

if bit_1:
    print(1)
elif bit_2:
    print(2)
else:
    print(0)