#include <bits/stdc++.h>
//#include <atcoder/all>
//using namespace atcoder;
#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
const double pi = 3.141592653589793238462643383279;
using namespace std;
//typedef
//------------------------------------------
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef pair<long long, long long> PLL;
typedef pair<int, PII> TIII;
typedef long long LL;
typedef unsigned long long ULL;
typedef vector<LL> VLL;
typedef vector<VLL> VVLL;

//container util
//------------------------------------------
#define ALL(a) (a).begin(), (a).endf()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define SQ(a) ((a) * (a))
#define EACH(i, c) for (typeof((c).begin()) i = (c).begin(); i != (c).endf(); ++i)
#define EXIST(s, e) ((s).find(e) != (s).endf())
#define SORT(c) sort((c).begin(), (c).endf())

//repetition
//------------------------------------------
#define FOR(i, s, n) for (int i = s; i < (int)n; ++i)
#define REP(i, n) FOR(i, 0, n)
#define MOD 1000000007

#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define trav(a, x) for (auto &a : x)
#define all(x) x.begin(), x.end()

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;

#define chmin(x, y) x = min(x, y)
#define chmax(x, y) x = max(x, y)
const double EPS = 1e-4, PI = acos(-1);
//ここから編集    
typedef string::const_iterator State;
template< int mod >
struct ModInt {
  int x;

  ModInt() : x(0) {}

  ModInt(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}

  ModInt &operator+=(const ModInt &p) {
    if((x += p.x) >= mod) x -= mod;
    return *this;
  }

  ModInt &operator-=(const ModInt &p) {
    if((x += mod - p.x) >= mod) x -= mod;
    return *this;
  }

  ModInt &operator*=(const ModInt &p) {
    x = (int) (1LL * x * p.x % mod);
    return *this;
  }

  ModInt &operator/=(const ModInt &p) {
    *this *= p.inverse();
    return *this;
  }

  ModInt operator-() const { return ModInt(-x); }

  ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }

  ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }

  ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }

  ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }

  bool operator==(const ModInt &p) const { return x == p.x; }

  bool operator!=(const ModInt &p) const { return x != p.x; }

  ModInt inverse() const {
    int a = x, b = mod, u = 1, v = 0, t;
    while(b > 0) {
      t = a / b;
      swap(a -= t * b, b);
      swap(u -= t * v, v);
    }
    return ModInt(u);
  }

  ModInt pow(int64_t n) const {
    ModInt ret(1), mul(x);
    while(n > 0) {
      if(n & 1) ret *= mul;
      mul *= mul;
      n >>= 1;
    }
    return ret;
  }

  friend ostream &operator<<(ostream &os, const ModInt &p) {
    return os << p.x;
  }

  friend istream &operator>>(istream &is, ModInt &a) {
    int64_t t;
    is >> t;
    a = ModInt< mod >(t);
    return (is);
  }

  static int get_mod() { return mod; }
};

using modint = ModInt< 998244353 >;
template< typename T >
struct Combination {
  vector< T > _fact, _rfact, _inv;

  Combination(int sz) : _fact(sz + 1), _rfact(sz + 1), _inv(sz + 1) {
    _fact[0] = _rfact[sz] = _inv[0] = 1;
    for(int i = 1; i <= sz; i++) _fact[i] = _fact[i - 1] * i;
    _rfact[sz] /= _fact[sz];
    for(int i = sz - 1; i >= 0; i--) _rfact[i] = _rfact[i + 1] * (i + 1);
    for(int i = 1; i <= sz; i++) _inv[i] = _rfact[i] * _fact[i - 1];
  }

  inline T fact(int k) const { return _fact[k]; }

  inline T rfact(int k) const { return _rfact[k]; }

  inline T inv(int k) const { return _inv[k]; }

  T P(int n, int r) const {
    if(r < 0 || n < r) return 0;
    return fact(n) * rfact(n - r);
  }

  T C(int p, int q) const {
    if(q < 0 || p < q) return 0;
    return fact(p) * rfact(q) * rfact(p - q);
  }

  T H(int n, int r) const {
    if(n < 0 || r < 0) return (0);
    return r == 0 ? 1 : C(n + r - 1, r);
  }
};
template <typename Monoid>
struct SegmentTree{

  int N;
  vector<Monoid> node;
  Monoid Unit;
  function<Monoid(Monoid, Monoid)> f;

  SegmentTree(vector<Monoid> v, const function<Monoid(Monoid, Monoid)> f, const Monoid &Unit): f(f), Unit(Unit){
    int sz_ = v.size();
    N = 1;
    while(N < sz_) N *= 2;

    node.assign(2*N, Unit);
    for(int i=0; i<sz_; i++) node[i+N-1] = v[i];
    for(int i=N-2; i>=0; i--) node[i] = f(node[2*i+1], node[2*i+2]);
  }

  void update(int k, const Monoid &x) {
    k += N-1;
    node[k] = x;
    while(k > 0){
      k = (k-1)/2;
      node[k] = f(node[2*k+1], node[2*k+2]);
    }
  }

  Monoid query(int a, int b, int k=0, int l = 0, int r=-1){
    if(r < 0) r = N;
    if(r <= a || b <= l) return Unit;
    
    if(a <= l && r <= b) return node[k];
    else{

      Monoid vl = query(a, b, 2*k+1, l, (l+r)/2);
      Monoid vr = query(a, b, 2*k+2, (l+r)/2, r);
      return f(vl, vr);
    }
  }
};

int f(auto& vp, int N){
    vector<int> tmp(N, 0);
    SegmentTree<int> seg(tmp, [&](int a, int b){return max(a, b);}, 0);
    int res = 0;
    REP(i,vp.size()){
      int idx = vp[i].second;
      int mx = min(seg.query(0, idx), seg.query(idx+1, N));
      res = max(res, mx);
      seg.update(idx, mx+1);
    }
    return res;
}
int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(15);

    int N; cin >> N;
    vector<int> a(N);
    REP(i,N) cin >> a[i];
    vector<pair<int, int>> vp;
    REP(i,N) vp.push_back({a[i], i});
    sort(all(vp));    
    int t1 = f(vp, N);
    reverse(all(vp));
    int t2 = f(vp, N);
    cout << max(t1, t2) << endl;
    
    return 0;
}