#include <algorithm>
#include <iostream>
#include <cstdio>
#include <map>
#include <numeric>
#include <cmath>
#include <set>
#include <sstream>
#include <string>
#include <vector>
#include <queue>
#include <stack>
#include <complex>
#include <string.h>
#include <unordered_set>
#include <unordered_map>
#include <bitset>
#include <iomanip>
#include <sys/time.h>
#include <random>
using namespace std;

#define endl '\n'
#define ALL(v) (v).begin(), (v).end()
#define RALL(v) (v).rbegin(), (v).rend()
#define UNIQ(v) (v).erase(unique((v).begin(), (v).end()), (v).end())

typedef long long ll;
typedef long double ld;
typedef pair<int, int> P;
typedef complex<double> comp;
typedef vector< vector<ld> > matrix;
struct pairhash {
public:
    template<typename T, typename U>
    size_t operator()(const pair<T, U> &x) const {
	size_t seed = hash<T>()(x.first);
	return hash<U>()(x.second) + 0x9e3779b9 + (seed<<6) + (seed>>2);
    }
};
const int inf = 1e9 + 9;
const ll mod = 1e9 + 7;
const double eps = 1e-8;
const double pi = acos(-1);

int n;
int a[3010];

int dp[2][3010][3010];

int calc(int b, int l, int r) {
    if (dp[b][l][r] < 0) {
        if (l == r) dp[b][l][r] = 1;
        else {
            int res = 0;
            if (b == 0 && a[l] >= a[r]) res = calc(b, l, r-1);
            else if (b == 1 && a[l] <= a[r]) res = calc(b, l+1, r);
            else if (b == 0) res = max(res, max(calc(b, l, r-1), calc(1-b, l+1, r)+1));
            else res = max(res, max(calc(b, l+1, r), calc(1-b, l, r-1)+1));
            dp[b][l][r] = res;
        }
    }
    return dp[b][l][r];
}

int solve() {
    int res = 0;
    memset(dp, -1, sizeof(dp));
    for (int i = 0; i < n; i++) {
        for (int j = i+1; j < n; j++)
            res = max(res, max(calc(0, i, j), calc(1, i, j)));
    }
    return res;
}

void input() {
    cin >> n;
    for (int i = 0; i < n; i++) cin >> a[i];
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << fixed << setprecision(15);

    input();
    cout << solve() << endl;
}