import bisect
N=int(input())
A=list(map(int,input().split()))
def f(n,a):
    ret=0
    def g(n,a):
        dp=[10**20]*n
        A=[0]*n
        for i in range(n):
            to=bisect.bisect_left(dp,a[i])
            dp[to]=a[i]
            A[i]=to
        return A
    L=g(n,a)
    R=g(n,a[::-1])[::-1]
    for i in range(n):
        ret=max(ret,min(L[i],R[i]))
    return ret

ans=f(N,A)
for i in range(N):
    A[i]=-A[i]
ans=max(ans,f(N,A))
print(ans)