/**
 *    author  : cr11htxuanson
 *    created : 20.09.2018
**/
#include <bits/stdc++.h>

using namespace std;

const int MAX = 50005;
const int N = 50050;
int n;
int A[N];
int F[5][N];
int T[5][4 * N];
int dp[5][N];

void Input()
{
	cin >> n;
	for (int i = 1; i <= n; i++) cin >> A[i];
}

void Subtask2()
{
	memset(F, -1, sizeof(F));
	for (int i = 1; i <= n; i++) F[1][i] = 1;
	for (int i = 2; i <= n; i++) {
		for (int j = 1; j < i; j++) {
			if (A[i] > A[j]) F[1][i] = max(F[1][i], F[1][j] + 1);
		}
		for (int j = 1; j < i; j++) {
			if (A[i] > A[j]) continue;
			if (F[1][j] >= 2) F[2][i] = max(F[2][i], F[1][j] + 1);
			if (F[2][j] != -1) F[2][i] = max(F[2][i], F[2][j] + 1);
		}
		for (int j = 1; j < i; j++) {
			if (A[i] < A[j]) continue;
			if (F[2][j] != -1) F[3][i] = max(F[3][i], F[2][j] + 1);
			if (F[3][j] != -1) F[3][i] = max(F[3][i], F[3][j] + 1);
		}
		for (int j = 1; j < i; j++) {
			if (A[i] > A[j]) continue;
			if (F[3][j] != -1) F[4][i] = max(F[4][i], F[3][j] + 1);
			if (F[4][j] != -1) F[4][i] = max(F[4][i], F[4][j] + 1);
		}
	}
	int ans = 0;
	for (int i = 1; i <= n; i++) ans = max(ans, F[4][i]);
	cout << ans;
}

void Roirac()
{
	map <int, int> Map;
	set <int> Set;
	set <int> :: iterator it;
	for (int i = 1; i <= n; i++) Set.insert(A[i]);
	int cnt = 0;
	for (it = Set.begin(); it != Set.end(); it++) {
		cnt++;
		int val = *it;
		Map[val] = cnt;
	}
	for (int i = 1; i <= n; i++) A[i] = Map[A[i]];
}

void update(int id, int node, int l, int r, int ql, int qr, int val)
{
	if (l > qr || r < ql) return;
	if (l >= ql && r <= qr) {
		T[id][node] = val;
		return;
	}
	int mid = (l + r) >> 1;
	update(id, node + node, l, mid, ql, qr, val);
	update(id, node + node + 1, mid + 1, r, ql, qr, val);
	T[id][node] = max(T[id][node + node], T[id][node + node + 1]);
}

int get(int id, int node, int l, int r, int ql, int qr)
{
	if (l > qr || r < ql) return 0;
	if (l >= ql && r <= qr) return T[id][node];
	int mid = (l + r) >> 1;
	int x = get(id, node + node, l, mid, ql, qr);
	int y = get(id, node + node + 1, mid + 1, r, ql, qr);
	return max(x, y);
}

void Lastsub()
{
	Roirac();
	memset(T, -1, sizeof(T));
	for (int i = 2; i <= n; i++) {
		int val_1 = get(1, 1, 1, n, 1, A[i] - 1);
		int val_2 = max(get(1, 1, 1, n, A[i] + 1, MAX), get(2, 1, 1, n, A[i] + 1, MAX));
		int val_3 = max(get(2, 1, 1, n, 1, A[i] - 1), get(3, 1, 1, n, 1, A[i] - 1));
		int val_4 = max(get(3, 1, 1, n, A[i] + 1, MAX), get(4, 1, 1, n, A[i] + 1, MAX));
		dp[1][i] = val_1 + 1;
		if (val_2 >= 2) dp[2][i] = val_2 + 1;
		if (val_3 >= 3) dp[3][i] = val_3 + 1;
		if (val_4 >= 4) dp[4][i] = val_4 + 1;
		update(1, 1, 1, n, A[i], A[i], dp[1][i]);
		update(2, 1, 1, n, A[i], A[i], dp[2][i]);
		update(3, 1, 1, n, A[i], A[i], dp[3][i]);
		update(4, 1, 1, n, A[i], A[i], dp[4][i]);
	}
	int ans = 0;
	for (int i = 1; i <= n; i++) ans = max(ans, dp[4][i]);
	cout << ans;
}

void Output()
{
	// /Subtask2();
	if (n <= 1000) {
		Subtask2();
		return;
	}
	Lastsub();
}

int main()
{
	ios :: sync_with_stdio(false);
	cin.tie(0); cout.tie(0);

	// freopen ("M.inp", "r", stdin);
	// freopen ("M.out", "w", stdout);

	Input(); Output();

	return 0;
}