N = int(input())
lsA = list(map(int,input().split()))
dp = [[0,0] for i in range(N)]
dp[0][1] = 1
for i in range(1,N):
    if lsA[i] == lsA[i-1]:
        dp[i][1] = max(dp[i-1][1]+1,dp[i-1][0])
        dp[i][0] = max(dp[i-1][1],dp[i-1][0])
    else:
        dp[i][1] = max(dp[i-1][0]+1,dp[i-1][0])
        dp[i][0] = max(dp[i-1][1],dp[i-1][0])
print(max(dp[N-1]))