import java.util.Scanner;
 
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
 
        // Read the number of elements
        int n = scanner.nextInt();
        // Initialize arrays to store values, prefix sums, and maximums
        int[] b = new int[n + 1]; // Original array
        int[] p = new int[n + 1]; // Array to store maximum prefix sums
        int[] s = new int[n + 1]; // Array to store sums of increasing sequences
        int[] u = new int[n + 1]; // Array to store maximum values at each index
        int[] max_s = new int[n + 1]; // Array to store maximum sums from index i to n
 
        // Input the values into the array b
        for (int i = 1; i <= n; i++) {
            b[i] = scanner.nextInt();
        }
 
        // Calculate the maximum prefix sums
        // p[i] will store the maximum sum of subarrays ending at index i
        p[1] = b[1]; // Base case: the first element is the only subarray
        for (int i = 2; i <= n; i++) {
            // Either take the current element or extend the previous maximum sum
            p[i] = Math.max(b[i], p[i - 1] + b[i]);
        }
 
        // Initialize the last elements for further calculations
        s[n] = b[n]; // Start with the last element
        u[n] = s[n]; // Initialize u[n] as well
 
        // Calculate sums of increasing sequences and their maximums
        for (int j = n - 1; j >= 1; j--) {
            // If the current element is less than the next, add to the sum
            if (b[j] < b[j + 1]) {
                s[j] = b[j] + s[j + 1]; // Extend the increasing sequence
            } else {
                s[j] = b[j]; // Start a new sequence
            }
 
            // Store the maximum value between the current element and the sum
            u[j] = Math.max(b[j], s[j]);
            // Update the maximum sums from index j to n
            max_s[j] = Math.max(u[j], max_s[j + 1]);
        }
 
        // Variable to store the final answer
        int answer = 0;
 
        // Calculate the maximum possible sum by combining prefix sums and maximum suffix sums
        for (int i = 1; i <= n - 1; i++) {
            // Combine the maximum prefix sum up to i and the maximum suffix sum from i+1
            int l = p[i] + max_s[i + 1];
            // Update the answer if the current combination is larger
            answer = Math.max(answer, l);
        }
 
        // Output the final answer
        System.out.println(answer);
    }
}
 

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