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

dp = [[0] * 2 for _ in range(N)]
dp[0][1] = 1
dp[0][0] = 0

for i in range(1,N):
    if A[i] == A[i-1]:
        dp[i][1] = max(dp[i-1][0],dp[i-1][1]) + 1
        dp[i][0] = max(dp[i-1][0],dp[i-1][1])
    else:
        dp[i][1] = dp[i-1][0] + 1
        dp[i][0] = max(dp[i-1][0],dp[i-1][1])
print(max(dp[-1]))