import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] arr = new int[n];
        int[] lds = new int[n + 1];
        int maxD = 0;
        lds[0] = Integer.MAX_VALUE;
        int[] lis = new int[n + 1];
        Arrays.fill(lis, Integer.MAX_VALUE);
        lis[0] = 0;
        int maxI = 0;
        int[] leftMaxesI = new int[n];
        int[] leftMaxesD = new int[n];
        for (int i = 0; i < n; i++) {
            arr[i] = sc.nextInt();
            for (int j = maxI; j >= 0; j--) {
                if (lis[j] < arr[i]) {
                    lis[j + 1] = Math.min(lis[j + 1], arr[i]);
                    maxI = Math.max(maxI, j + 1);
                    break;
                }
            }
            leftMaxesI[i] = maxI;
            for (int j = maxD; j >= 0; j--) {
                if (lds[j] > arr[i]) {
                    lds[j + 1] = Math.max(lds[j + 1], arr[i]);
                    maxD = Math.max(maxD, j + 1);
                    break;
                }
            }
            leftMaxesD[i] = maxD;
        }
        Arrays.fill(lds, 0);
        lds[0] = Integer.MAX_VALUE;
        Arrays.fill(lis, Integer.MAX_VALUE);
        lis[0] = 0;
        maxD = 0;
        maxI = 0;
        int ans = 0;
        for (int i = n - 1; i >= 0; i--) {
            for (int j = maxI; j >= 0; j--) {
                if (lis[j] < arr[i]) {
                    lis[j + 1] = Math.min(lis[j + 1], arr[i]);
                    maxI = Math.max(maxI, j + 1);
                    break;
                }
            }
            ans = Math.max(ans, Math.min(leftMaxesI[i], maxI) - 1);
            for (int j = maxD; j >= 0; j--) {
                if (lds[j] > arr[i]) {
                    lds[j + 1] = Math.max(lds[j + 1], arr[i]);
                    maxD = Math.max(maxD, j + 1);
                    break;
                }
            }
            ans = Math.max(ans, Math.min(leftMaxesD[i], maxD) - 1);
        }
        System.out.println(ans);
    }
}