#include <bits/stdc++.h>
using namespace std;


int N, A[3010];
int memo[3010][3010][2];

int len(int l, int r, int sign) {
    if (memo[l][r][sign] != -1)
        return memo[l][r][sign];
    if (l == r)
        return 1;
    int tmp = 1;
    if (sign) {
        for (int x = l; x <= r - 1; x++) {
            if (A[x] > A[r])
                tmp = max(tmp, len(x, r - 1, !sign) + 1);
        }
    } else {
        for (int x = l + 1; x <= r; x++) {
            if (A[x] > A[l])
                tmp = max(tmp, len(l + 1, x, !sign) + 1);
        }
    }
    return memo[l][r][sign] = tmp;
}

int main() {
    cin >> N;
    for (int i = 0; i < N; i++) {
        cin >> A[i];
    }

    for (int i = 0; i < N; i++)
        for (int j = 0; j < N; j++)
            for (int k = 0; k < 2; k++)
                memo[i][j][k] = -1;

    cout << max(len(0, N - 1, 0), len(0, N - 1, 1)) << endl;
}