#include <bits/stdc++.h>
#define GET_MACRO(a, b, c, NAME, ...) NAME
#define rep(...) GET_MACRO(__VA_ARGS__, rep3, rep2)(__VA_ARGS__)
#define rep2(i, a) rep3 (i, 0, a)
#define rep3(i, a, b) for (int i = (a); i < (b); i++)
#define repr(...) GET_MACRO(__VA_ARGS__, repr3, repr2)(__VA_ARGS__)
#define repr2(i, a) repr3 (i, 0, a)
#define repr3(i, a, b) for (int i = (b) - 1; i >= (a); i--)
#define chmin(a, b) ((b) < a && (a = (b), true))
#define chmax(a, b) (a < (b) && (a = (b), true))
using namespace std;
typedef long long ll;

int dplr[3030][3030]; // LRL...
int dprl[3030][3030]; // RLR...

int main() {
	int N;
	cin >> N;
	vector<int> A(N);
	rep (i, N) cin >> A[i];
	rep (i, N) {
		rep (j, N - i) {
			int k = j + i;
			// [j,k]
			if (j == k) dplr[j][k] = dprl[j][k] = 1;
			else {
				dprl[j][k] = dprl[j + 1][k];
				dplr[j][k] = dplr[j][k - 1];
				if (A[j] < A[k]) {
					dplr[j][k] = max(dprl[j + 1][k] + 1, dplr[j][k - 1]);
				}
				if (A[j] > A[k]) {
					dprl[j][k] = max(dplr[j][k - 1] + 1, dprl[j + 1][k]);
				}
			}
		}
	}
	int ans = 0;
	rep (i, N) rep (j, N) {
		chmax(ans, dplr[i][j]);
		chmax(ans, dprl[i][j]);
	}
	cout << ans << endl;
	return 0;
}