import bisect


def LIS(lists):
    N = len(lists)
    inf = 10**15
    dp = [inf for i in range(N+1)]
    length = [0 for i in range(N)]
    for i in range(N):
        index = bisect.bisect_left(dp, lists[i])
        dp[index] = lists[i]
        length[i] = index + 1
    return length


def LDS(lists):
    L = [-x for x in lists]
    return LIS(L)


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

left_upper = LIS(A)
left_downer = LDS(A)

A.reverse()

right_upper = LIS(A)
right_downer = LDS(A)

ans = 0

for i in range(N):
    ans = max(ans, min(left_upper[i], right_upper[N-1-i]),
              min(left_downer[i], right_downer[N-1-i]))

print(ans - 1)