from bisect import *
def solve1182():
  print('kaage')

def solve1183():
  N=int(input())
  A=list(map(int,input().split()))
  B=list(map(int,input().split()))
  for i in range(N):
    A[i]^=B[i]
  P=A[0]
  for i in range(N-1):
    if A[i]==0 and A[i+1]==1:
      P+=1
  print(P)

def solve1184():
  N,L=map(int,input().split())
  print(pow(2,(N+L-1)//L,998244353)-1)

def solve1185():
  N=int(input())
  i=0
  r=(1<<20)
  P=-4
  j=0
  k=0
  while(i<r):
    j=i
    k=0
    for l in range(10):
      k+=((j&3)*3*(10**l))
      j>>=2
    if N>=k:
      P+=1
    else:
      break
    i+=1
  for i in range(10):
    for j in range(10):
      if i%3 and j%3 and (i+j)%3==0:
        if i*10+j<=N:
          P+=1
  print(P)

def solve1186():
  N,M=map(int,input().split())
  if N==1:
    print(1)
    exit()
  mod=998244353
  DP=[0]*(M+1)
  DP[0]=1
  for i in range(M):
    DP[i+1]=(DP[i]+DP[i+1])%mod
    if i+N<=M:
      DP[i+N]=DP[i]
  print(DP[-1])

def solve1187():
  L,R=0,1000
  X=0
  S=0
  T=0
  while R-L>1:
    X=(L+R)//2
    print('?',X)
    S=input()
    print('?',X+1)
    T=input()
    if T=='out' and S=='out':
      R=X
    elif S=='safe' and T=='out':
      L=X
    else:
      L=X+1
  print('?',R)
  if input()=='out':
    print('!',L)
  else:
    print('!',R)

def solve1188():
  def LIS(A):
    N=len(A)
    R=[]
    INF=10**17
    DP=[INF]*(N+1)
    DP[0]=-INF
    for i in range(N):
      R.append(bisect_left(DP,A[i]))
      DP[R[i]]=A[i]
    return R
  
  N=int(input())
  A=list(map(int,input().split()))
  B=A[::-1]
  C=[-A[i] for i in range(N)]
  D=C[::-1]
  A=LIS(A)
  B=LIS(B)
  C=LIS(C)
  D=LIS(D)
  print(max([max(min(A[i],B[-i-1]),min(C[i],D[-1-i])) for i in range(N)])-1)

solve1188()