#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef pair<ll, ll> p_ll;

template<class T>
void debug(T itr1, T itr2) { auto now = itr1; while(now<itr2) { cout << *now << " "; now++; } cout << endl; }
#define repr(i,from,to) for (ll i=(ll)from; i<(ll)to; i++)
#define all(vec) vec.begin(), vec.end()
#define rep(i,N) repr(i,0,N)
#define per(i,N) for (int i=(int)N-1; i>=0; i--)

const ll MOD = pow(10,9)+7;
const ll LLINF = pow(2,61)-1;
const int INF = pow(2,30)-1;

vector<ll> fac;
void c_fac(int x=pow(10,6)+10) { fac.resize(x,true); rep(i,x) fac[i] = i ? (fac[i-1]*i)%MOD : 1; }
ll modpow(ll x, ll p) { ll result = 1, now = 1, pm = x; while (now<=p) { if (p&now) { result = result * pm % MOD; } now*=2; pm = pm*pm % MOD; } return result; }
ll inv(ll a, ll m=MOD) { ll b = m, x = 1, y = 0; while (b!=0) { int d = a/b; a -= b*d; swap(a,b); x -= y*d; swap(x,y); } return (x+m)%m; }
ll nck(ll n, ll k) { return fac[n]*inv(fac[k]*fac[n-k]%MOD)%MOD; }
ll gcd(ll a, ll b) { if (a<b) swap(a,b); return b==0 ? a : gcd(b, a%b); }
ll lcm(ll a, ll b) { return a/gcd(a,b)*b; }


int main() {
  ll N; cin >> N;
  ll A[N]; rep(i,N) cin >> A[i];

  vector<ll> d1(N,LLINF), d2(N,LLINF);
  vector<ll> dp1(N), dp2(N);
  rep(i,N) {
    dp1[i] = lower_bound(all(d1),A[i]) - d1.begin();
    d1[dp1[i]] = A[i];
  }
  per(i,N) {
    dp2[i] = lower_bound(all(d2),A[i]) - d2.begin();
    d2[dp2[i]] = A[i];
  }
  // debug(all(d1)); debug(all(dp1));
  // debug(all(d2)); debug(all(dp2));

  vector<ll> d3(N,LLINF), d4(N,LLINF);
  vector<ll> dp3(N), dp4(N);
  rep(i,N) {
    dp3[i] = lower_bound(all(d3),-1*A[i]) - d3.begin();
    d3[dp3[i]] = -1*A[i];
  }
  per(i,N) {
    dp4[i] = lower_bound(all(d4),-1*A[i]) - d4.begin();
    d4[dp4[i]] = -1*A[i];
  }
  // debug(all(d3)); debug(all(dp3));
  // debug(all(d4)); debug(all(dp4));

  ll result = 0; rep(i,N) result = max(result, max(min(dp1[i],dp2[i]), min(dp3[i],dp4[i])));
  cout << result << endl;
  return 0;
}