10
-3 4 -4 1 1 -4 -5 3 -4 -2
 10
8 9 -10 -10 -4 -3 5 9 -9 9
 6
5 -4 2 -1 2 -2
 11
3 0 1 -2 5 -5 -1 0 3 2 2
 10
4 -2 -2 -2 2 0 1 0 -4 -1
 4
2 2 -3 4
 11
-11 -7 -2 -24 30 -26 24 9 -8 -9 23
 6
30 -29 5 5 -29 30
 24
-8 -6 6 -11 -15 -7 10 -19 -6 21 14 -4 -21 -10 12 17 1 -1 5 19 2 0 -4 -23
 10
-9 -6 -1 9 -2 0 0 -1 5 0
 6
10 -8 3 3 -8 10
 10
-2 -3 -1 4 -3 2 0 1 -5 4
 5
30 -29 10 -1 10
 31
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 -29 30
 7
30 -20 5 1 3 -20 30
 5
30 -29 4 -3 4
 10
-5 28 -18 -10 9 -2 11 -6 -19 30
 8
4 -10 13 -13 2 2 -11 6
 131
30 -29 29 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 27 -26 27
 10
-4 4 0 -2 3 0 1 2 3 -4
 10
-2 -8 5 4 -1 -6 -9 6 1 -6
 7
25 -17 13 13 -25 25 -24
 10
3 -3 2 1 -4 -2 3 -2 -3 0
 10
4 -5 0 4 0 0 -3 1 1 -4
 10
0 4 4 1 -3 4 2 1 4 -1
 17
15 -13 7 8 8 1 -19 12 8 -23 -4 16 -13 -28 10 -30 -14
 4
1 1 -4 10
 11
3 -2 1 1 1 1 1 1 1 -3 4
 7
30 -29 10 10 10 -29 30
 7
25 -13 17 -23 12 12 9
 7
15 -14 10 10 10 -14 15
 10
3 0 0 -4 3 1 -2 -1 -1 4
 6
8 -7 7 -6 5 5
 10
1 -4 -4 4 -2 -3 3 0 -2 3
 15
1 -26 -6 26 7 10 -2 -4 -6 14 -9 25 9 -12 -28
 6
30 -29 10 10 -29 30
 1
6
 2
1 1
 5
0 5 -4 3 -1
 7
5 -4 3 -1 3 -4 4
 10
16 -15 13 -1 10 -2 -20 26 5 -30
 10
-1 2 0 -1 2 -1 4 3 -5 1
 7
5 -4 1 1 1 -4 5
 5
10 -3 -5 3 5
 10
4 -4 3 -2 3 -4 -2 0 1 0
 10
-5 -5 -3 1 -2 2 0 2 -3 4
 10
2 -4 -2 3 1 1 -2 -1 -3 4
 10
-4 -5 4 -3 2 -2 2 1 -1 0
 10
0 -1 4 -2 3 -2 -1 -5 -5 2
 5
19 -6 1 -11 19
 10
1 0 -4 3 -5 3 -1 2 2 -5
 7
5 -5 3 4 3 -5 5
 10
-5 2 -3 -3 -4 3 3 0 2 4
 4
2 3 -10 11
 10
27 -17 15 -22 18 17 -6 2 16 -14
 6
30 -22 6 7 -22 30
 7
30 -25 0 6 9 -2 10
 9
7 2 -1 1 1 -10 6 -1 6
 4
1 -10 1 10
 5
17 -16 12 -11 15
 35
-23 -22 23 4 -22 29 -4 -6 -28 18 -5 21 -7 -8 -11 -7 30 -25 -1 12 19 5 -8 12 -1 10 -24 -19 24 -17 -7 24 20 -22 16
 10
4 -3 1 -2 1 1 0 -4 4 -2
 10
4 -2 1 0 1 -5 -2 1 0 -5
 2
3 9
 9
11 -5 -5 1 2 3 -5 -5 11

1
 8
 1
 4
 1
 2
 15
 5
 36
 2
 3
 1
 9
 28
 4
 1
 7
 2
 1
 7
 4
 13
 1
 1
 13
 16
 1
 6
 20
 21
 20
 1
 5
 1
 44
 10
 0
 1
 0
 2
 9
 5
 2
 3
 1
 2
 2
 1
 1
 3
 3
 6
 8
 2
 29
 6
 13
 5
 1
 1
 30
 1
 1
 3
 3

import java.util.*;
import java.io.*;
public class D{
	
	static class LineTree{
		static class Node{
			int l;
			int r;
			int max;
			Node(int l, int r, int max){
				this.l = l;
				this.r = r;
				this.max = max;
			}
			
			public String toString(){
				return new Formatter().format("(%d,%d,%d)",l,r,max).toString();
			}
		}
		
		
		Node[] arr;
		int size;
		// int n;
		LineTree(int n, int[] a){
			int powOf2Count = 0;
			int powOf2=1;
			while(powOf2 < n){
				powOf2*=2;
				powOf2Count++;
			}
			// this.n = n;
			size = n;
			arr = new Node[powOf2*2-1];
			arr[0] = new Node(0,powOf2-1,Integer.MIN_VALUE);
			constructTree(0,a);
		}
		
		void constructTree(int i,int[] a){
			if(arr[i].l == arr[i].r){
				if(arr[i].l >= size) arr[i].max = Integer.MIN_VALUE;
				else arr[i].max = a[arr[i].l];
				return;
			}
			int l = arr[i].l;
			int r = arr[i].r;
			
			arr[i*2 +1 ] = new Node(l,(r+l)/2,Integer.MIN_VALUE);
			arr[i*2 +2 ] = new Node((r+l)/2+1,r,Integer.MIN_VALUE);
			constructTree(i*2+1,a);
			constructTree(i*2+2,a);
			arr[i].max = Math.max(arr[i*2 +1 ].max,arr[i*2 +2 ].max);
		}
		
		int max(int l, int r, int i){
			// System.out.println(new Formatter().format("%d:(%d,%d)", i, l, r).toString());
			
			if(arr[i].l ==l && arr[i].r ==r){
				return arr[i].max;
			}
			int max = Integer.MIN_VALUE;
			if(arr[2*i+1].r >= l)
				max = Math.max(max, max(l,Math.min(arr[2*i+1].r,r),2*i+1));
			if(arr[2*i+2].l <= r)
				max = Math.max(max, max(Math.max(arr[2*i+2].l,l),r,2*i+2));
			return max;
		}
		
		public String toString(){
			return Arrays.toString(arr);
		}
		
	}
	static class Pair{
		int x;
		int y;
		Pair(int n){
			x = 0;
			y = n-1;
		}
		public String toString(){
			return new Formatter().format("(%d,%d)",x,y).toString();
		}
	}
	
	
	public static void main(String[] args){
		Scanner in = new Scanner(System.in);
		int n = in.nextInt();
		
		
		int[] a = new int[n];
		int[] pref = new int[n];
		Pair[] lines = new Pair[n];
		int[] indeses = new int[61];
		for(int i = 0;i<n;++i){
			a[i] = in.nextInt();
			lines[i] = new Pair(n);
			for(int j = a[i] + 30 + 1;j<61;++j){
				lines[i].x = Math.max(lines[i].x, indeses[j]);
			}
			indeses[a[i]+30] = i+1;
			if(i == 0) pref[0] = a[0];
			else pref[i] = pref[i-1] + a[i];
		}
		for(int i = 0;i<61;++i){
			indeses[i] = n;
		}
		int[] suf = new int[n];
		for(int i = n-1;i>=0;--i){
			for(int j = a[i] + 30+ 1;j<61;++j){
				lines[i].y = Math.min(lines[i].y, indeses[j]);
			}
			indeses[a[i]+30] = i-1;
			if(i == n-1) suf[i] = a[i];
			else suf[i] = suf[i+1] + a[i];
			
		}
		
		// System.out.println(Arrays.toString(lines));
		LineTree preft = new LineTree(n,pref);
		// System.out.println(Arrays.toString(pref));
		// // System.out.println(preft);
		// // System.out.println(preft.max(0,3,0));
		// // System.out.println(preft.max(1,3,0));
		// // System.out.println(preft.max(3,3,0));
		// // System.out.println(preft.max(3,4,0));
		// // System.out.println(preft.max(4,4,0));
		// // System.out.println(preft.max(4,4,0));
		LineTree suft = new LineTree(n,suf);
		// System.out.println(Arrays.toString(suf));
		// System.out.println(suft);
		int res = 0;
		for(int i = 0;i<n;++i){
			Pair p = lines[i];
			int maxSum = suft.max(p.x,i,0) + preft.max(i,p.y,0);
			// System.out.println(i + " " + maxSum);
			maxSum  =maxSum -  suf[i] - pref[i];
			
			// System.out.println(new Formatter().format("%d:%d + %d = %d", i, suft.max(p.x,i,0),preft.max(i,p.y,0),maxSum).toString());
			res = Math.max(res, maxSum);
		}
		System.out.println(res);
		
	}
}