#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include<iostream>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<bitset>
#include<stack>
#include<unordered_map>
#include<unordered_set>
#include<utility>
#include<cassert>
#include<complex>
#include<numeric>
#include<array>
#include<chrono>
using namespace std;

//#define int long long
typedef long long ll;

typedef unsigned long long ul;
typedef unsigned int ui;
constexpr ll mod = 1000000007;
const ll INF = mod * mod;
typedef pair<int, int>P;

#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
#define all(v) (v).begin(),(v).end()
typedef pair<ll, ll> LP;

template<typename T>
void chmin(T& a, T b) {
	a = min(a, b);
}
template<typename T>
void chmax(T& a, T b) {
	a = max(a, b);
}
template<typename T>
void cinarray(vector<T>& v) {
	rep(i, v.size())cin >> v[i];
}
template<typename T>
void coutarray(vector<T>& v) {
	rep(i, v.size()) {
		if (i > 0)cout << " "; cout << v[i];
	}
	cout << "\n";
}
ll mod_pow(ll x, ll n, ll m = mod) {
	if (n < 0) {
		ll res = mod_pow(x, -n, m);
		return mod_pow(res, m - 2, m);
	}
	if (abs(x) >= m)x %= m;
	if (x < 0)x += m;
	if (x == 0)return 0;
	ll res = 1;
	while (n) {
		if (n & 1)res = res * x % m;
		x = x * x % m; n >>= 1;
	}
	return res;
}
struct modint {
	int n;
	modint() :n(0) { ; }
	modint(ll m) {
		if (m < 0 || mod <= m) {
			m %= mod; if (m < 0)m += mod;
		}
		n = m;
	}
	operator int() { return n; }
};
bool operator==(modint a, modint b) { return a.n == b.n; }
modint operator+=(modint& a, modint b) { a.n += b.n; if (a.n >= mod)a.n -= mod; return a; }
modint operator-=(modint& a, modint b) { a.n -= b.n; if (a.n < 0)a.n += mod; return a; }
modint operator*=(modint& a, modint b) { a.n = ((ll)a.n * b.n) % mod; return a; }
modint operator+(modint a, modint b) { return a += b; }
modint operator-(modint a, modint b) { return a -= b; }
modint operator*(modint a, modint b) { return a *= b; }
modint operator^(modint a, ll n) {
	if (n == 0)return modint(1);
	modint res = (a * a) ^ (n / 2);
	if (n % 2)res = res * a;
	return res;
}

ll inv(ll a, ll p) {
	return (a == 1 ? 1 : (1 - p * inv(p % a, a)) / a + p);
}
modint operator/(modint a, modint b) { return a * modint(inv(b, mod)); }
modint operator/=(modint& a, modint b) { a = a / b; return a; }
const int max_n = 1 << 20;
modint fact[max_n], factinv[max_n];
void init_f() {
	fact[0] = modint(1);
	for (int i = 0; i < max_n - 1; i++) {
		fact[i + 1] = fact[i] * modint(i + 1);
	}
	factinv[max_n - 1] = modint(1) / fact[max_n - 1];
	for (int i = max_n - 2; i >= 0; i--) {
		factinv[i] = factinv[i + 1] * modint(i + 1);
	}
}
modint comb(int a, int b) {
	if (a < 0 || b < 0 || a < b)return 0;
	return fact[a] * factinv[b] * factinv[a - b];
}
modint combP(int a, int b) {
	if (a < 0 || b < 0 || a < b)return 0;
	return fact[a] * factinv[a - b];
}

ll gcd(ll a, ll b) {
	a = abs(a); b = abs(b);
	if (a < b)swap(a, b);
	while (b) {
		ll r = a % b; a = b; b = r;
	}
	return a;
}
typedef long double ld;
typedef pair<ld, ld> LDP;
const ld eps = 1e-8;
const ld pi = acosl(-1.0);
int dx[4] = { 1,0,-1,0 };
int dy[4] = { 0,1,0,-1 };

using mP = pair<modint, modint>;
//-----------------------------------

template<typename T>
struct SegT {
private:
	int sz; vector<T> node;
	T init_c;
	function<T(T, T)> f;
public:
	SegT(vector<T> v, T _init_c, function<T(T, T)> _f) {
		init_c = _init_c; f = _f;
		int n = v.size();
		sz = 1;
		while (sz < n)sz *= 2;
		node.resize(2 * sz - 1, init_c);
		rep(i, n) {
			node[i + sz - 1] = v[i];
		}
		per(i, sz - 1) {
			node[i] = f(node[2 * i + 1], node[2 * i + 2]);
		}
	}
	SegT(int n, T _init_c, function<T(T, T)> _f) {
		init_c = _init_c; f = _f;
		sz = 1;
		while (sz < n)sz *= 2;
		node.resize(2 * sz - 1, init_c);
	}
	void update(int k, T a) {
		k += sz - 1;
		node[k] = a;
		while (k > 0) {
			k = (k - 1) / 2;
			node[k] = f(node[k * 2 + 1], node[k * 2 + 2]);
		}
	}
	T query(int a, int b, int k = 0, int l = 0, int r = -1) {
		if (r < 0)r = sz;
		if (r <= a || b <= l)return init_c;
		else if (a <= l && r <= b)return node[k];
		else {
			T vl = query(a, b, k * 2 + 1, l, (l + r) / 2);
			T vr = query(a, b, k * 2 + 2, (l + r) / 2, r);
			return f(vl, vr);
		}
	}
	//k以上でf(x,node[y+sz-1])をtrueにするような最小のy
	int searchloc(int le, T x, function<bool(T, T)> comp) {
		int  k = le + sz - 1;
		if (comp(x, node[k]))return le;
		x = f(x, node[k]);
		while (k > 0) {
			int mem = k;
			k = (k - 1) / 2;
			if (2 * k + 1 == mem) {
				if (comp(x, node[2 * k + 2])) {
					k = 2 * k + 2; break;
				}
				x = f(x, node[2 * k + 2]);
			}
		}
		if (k == 0)return sz;
		while (k < sz - 1) {
			if (comp(x, node[2 * k + 1])) {
				k = 2 * k + 1;
			}
			else {
				x = f(x, node[2 * k + 1]);
				k = 2 * k + 2;
			}
		}
		return k - (sz - 1);
	}
};

void solve() {
	int n; cin >> n;
	vector<int> a(n);
	rep(i, n) {
		cin >> a[i];
	}
	auto f = [&](P a, P b) {
		return max(a, b);
	};
	auto g = [&](P a, P b) {
		if (a.first < b.first)return b;
		if (a.first > b.first)return a;
		return min(a, b);
	};
	SegT<P> st(n + 1, P{ 0,-1 }, f);
	vector<int> val(n);
	vector<int> pre(n);
	rep(i, n) {
		P p = st.query(0, a[i]);
		pre[i] =p.second;
		val[i] = p.first + 1;
		st.update(a[i], { val[i],i });
	}
	int ma = 0;
	rep(i, n)chmax(ma, val[i]);
	vector<int> cnt(n);
	int cur = -1;
	per(i, n)if (val[i] == ma) {
		cur = i; break;
	}
	rep(i, ma) {
		cnt[cur]++;
		cur = pre[cur];
	}
	SegT<P> st2(n + 1, P{ 0,-1 }, g);
	rep(i, n) {
		P p = st2.query(0, a[i]);
		pre[i] = p.second;
		val[i] = p.first + 1;
		st2.update(a[i], { val[i],i });
	}
	cur = -1;
	rep(i, n)if (val[i] == ma) {
		cur = i; break;
	}
	rep(i, ma) {
		cnt[cur]++;
		cur = pre[cur];
	}
	vector<int> ans;
	rep(i, n)if (cnt[i] == 2)ans.push_back(a[i]);
	cout << ans.size() << "\n";
	coutarray(ans);
}


signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout << fixed << setprecision(10);
	//init_f();
	//init();
	//while(true)
	//expr();
	//int t; cin >> t; rep(i, t)
	solve();
	return 0;
}