#include 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; if (sign) { if (A[l] > A[r]) { tmp = max(len(l, r - 1, !sign) + 1, len(l + 1, r, sign)); } else tmp = len(l + 1, r, sign); } else { if (A[l] < A[r]) { tmp = max(len(l + 1, r, !sign) + 1, len(l, r - 1, sign)); } else tmp = len(l, r - 1, sign); } 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; }