N = int(input())
A = list(map(int,input().split()))
dp = [0 for _ in range(N)]
dp[0]=1
for i in range(1,N):
    if A[i]==A[i-1]:
        dp[i] = dp[i-1]+1
    else:
        dp[i]=dp[i-1]
        if i>=2:
            dp[i]=max(dp[i],dp[i-2]+1)
print(dp[N-1])