n = int(input())
a = [int(i) for i in input().split()]

dp = [0]*n
dp[0] = 1
if a[0] == a[1]:
    dp[1] = 2
else:
    dp[1] = 1

for i in range(2,n):
    if a[i-1] == a[i]:
        dp[i] = max(dp[i-1],dp[i-2])+1
    else:
        dp[i] = max(dp[i-1],dp[i-2]+1)
print(dp[n-1])