#include using namespace std; #define REP(i,n) for(ll i=0;i<(ll)n;i++) #define dump(x) cerr << #x << " = " << (x) << endl; #define spa << " " << #define fi first #define se second #define ALL(a) (a).begin(),(a).end() #define ALLR(a) (a).rbegin(),(a).rend() using ld = long double; using ll = long long; using ull = unsigned long long; using pii = pair; using pll = pair; using pdd = pair; template struct V : vector { using vector::vector; }; V() -> V; V(size_t) -> V; template V(size_t, T) -> V; template vector make_vec(size_t n, T a) { return vector(n, a); } template auto make_vec(size_t n, Ts... ts) { return vector(n, make_vec(ts...)); } template ostream& operator << (ostream& os, const pair v){os << "(" << v.first << ", " << v.second << ")"; return os;} template ostream& operator<<(ostream &os, const vector &v) { for (auto &e : v) os << e << ' '; return os; } template ostream& operator<<(ostream& os, const vector> &v){ for(auto &e : v){os << e << "\n";} return os;} struct fast_ios { fast_ios(){ cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_; template bool chmax(T &a, const T &b) { if (a bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; } void fail() { cout << -1 << '\n'; exit(0); } inline int popcount(const int x) { return __builtin_popcount(x); } inline int popcount(const ll x) { return __builtin_popcountll(x); } template void debug(vector>&v,ll h,ll w){for(ll i=0;i void debug(vector&v,ll n){if(n!=0)cerr<> N; V A(N); REP(i, N) cin >> A[i]; auto LIS = [](V &A){ ll N = A.size(); V dp(N, INF); V res(N); REP(i, N){ auto itr = lower_bound(ALL(dp), A[i]); *itr = A[i]; ll pos = lower_bound(ALL(dp), INF) - dp.begin(); res[i] = pos; } return res; }; auto solve = [&](V &A){ ll N = A.size(); auto d1 = LIS(A); reverse(ALL(A)); auto d2 = LIS(A); reverse(ALL(A)); reverse(ALL(d2)); ll res = 0; REP(i, N) chmax(res, min(d1[i], d2[i])-1); // dump(d1) // dump(d2) return res; }; auto res = solve(A); REP(i, N) A[i] *= -1; chmax(res, solve(A)); cout << res << endl; return 0; }