Alice and Bob are playing yet another card game. This time the rules are the following. There are n cards lying in a row in front of them. The i-th card has value a_i. 

First, Alice chooses a non-empty consecutive segment of cards [l; r] (l ≤ r). After that Bob removes a single card j from that segment (l ≤ j ≤ r). The score of the game is the total value of the remaining cards on the segment (a_l + a_{l + 1} + ... + a_{j - 1} + a_{j + 1} + ... + a_{r - 1} + a_r). In particular, if Alice chooses a segment with just one element, then the score after Bob removes the only card is 0.

Alice wants to make the score as big as possible. Bob takes such a card that the score is as small as possible.

What segment should Alice choose so that the score is maximum possible? Output the maximum score.

Input

The first line contains a single integer n (1 ≤ n ≤ 10^5) — the number of cards.

The second line contains n integers a_1, a_2, ..., a_n (-30 ≤ a_i ≤ 30) — the values on the cards.

Output

Print a single integer — the final score of the game.

Examples

Input


5
5 -2 10 -1 4


Output


6


Input


8
5 2 5 3 -30 -30 6 9


Output


10


Input


3
-10 6 -15


Output


0

Note

In the first example Alice chooses a segment [1;5] — the entire row of cards. Bob removes card 3 with the value 10 from the segment. Thus, the final score is 5 + (-2) + (-1) + 4 = 6.

In the second example Alice chooses a segment [1;4], so that Bob removes either card 1 or 3 with the value 5, making the answer 5 + 2 + 3 = 10.

In the third example Alice can choose any of the segments of length 1: [1;1], [2;2] or [3;3]. Bob removes the only card, so the score is 0. If Alice chooses some other segment then the answer will be less than 0.
import java.io.*;
import java.io.IOException;
import java.lang.Thread.State;
import java.util.*;
//import javafx.util.Pair; 
//import java.util.concurrent.LinkedBlockingDeque;






    
  public class Codeforces {
        
        public static long mod = (long)Math.pow(2,32) ;
        public static double epsilon=0.00000000008854;//value of epsilon
        public static InputReader sc = new InputReader(System.in);
        public static PrintWriter pw = new PrintWriter(System.out);
        
        public static ArrayList<ArrayList <Integer>> GetGraph(int n,int m){
            ArrayList<ArrayList <Integer>> g=new ArrayList<>();
            for(int i=0;i<n;i++){
                g.add(new ArrayList<>());
            }
            for(int i=0;i<m;i++){
                //int t=sc.nextInt();
                int u=sc.nextInt()-1;
                int v=sc.nextInt()-1;
                g.get(u).add(v);
                //if(t==0)
                g.get(v).add(u);
            }
            return g;
        }
        
        public static int find(int a,int p[]){
            if(a!=p[a]){
               p[a]=find(p[a], p);
            }
             return p[a];
        }
        public static void Union(int a,int b,int p[]){
            p[find(b, p)]=find(a, p);
        }
        public static long gcd(long a,long b){
            while(b>0){
                long t=b;
                b=a%b;
                a=t;
            }
            return a;
        }
        public static int dfs(ArrayList<ArrayList <Integer>> g,int u,int vis[],int p[],int down[]){
            vis[u]=1;
            int c=p[u];
            for(int i=0;i<g.get(u).size();i++){
                int v=g.get(u).get(i);
                if(vis[v]==0){
                    c+=dfs(g, v, vis, p, down);
                }
            }
            down[u]=c;
            return c;
        }
        
            
        public static void main(String[] args) {
            // code starts..

            int n=sc.nextInt();
            int a[]=scanArray(n);
            HashSet<Integer> h=new HashSet<>();
            for(int i=0;i<n;i++){
                h.add(a[i]);
            }
            int max=0;
            for(int i=0;i<=31;i++){
                int hv=0;
                int s=0;
                for(int j=0;j<n;j++){
                    s+=a[j];
                    if(a[j]==i){
                        hv=1;
                    }
                    if(s<0||a[j]>i){
                        s=0;
                        hv=0;
                    }
                    if(hv==1){
                        max=Math.max(s-i, max);
                    }
                }
            }
            pw.println(max);

            // Code ends...
            pw.flush();
            pw.close();
        }
       
        public static Comparator<Long[]> column(int i){
            return 
            new Comparator<Long[]>() {
                @Override
                public int compare(Long[] o1, Long[] o2) {
                    return o1[i].compareTo(o2[i]);//for ascending
                    //return o2[i].compareTo(o1[i]);//for descending
                }
            };
        }
        public static Comparator<Pair> C(){
            return 
            new Comparator<Pair>() {
                @Override
                public int compare(Pair o1, Pair o2) {
                    return o2.le-o1.le;//for des
                }
            };
        }
        
        public static Comparator<Integer[]> pair(){
            return 
            new Comparator<Integer[]>() {
                @Override
                public int compare(Integer[] o1, Integer[] o2) {
                    int result=o1[0].compareTo(o2[0]);
                    if(result==0)
                    result=o1[1].compareTo(o2[1]);
                    return result;
                }
            };
        }
        
        public static String reverseString(String s){
            StringBuilder input1 = new StringBuilder(); 
            input1.append(s);  
            input1 = input1.reverse();
            return input1.toString();
        }
        public static int[] scanArray(int n){
            int a[]=new int [n];
            for(int i=0;i<n;i++)
            a[i]=sc.nextInt();
    
            return a;
        }
        public static long[] scanLongArray(int n){
            long a[]=new long [n];
            for(int i=0;i<n;i++)
            a[i]=sc.nextLong();
    
            return a;
        }
        public static String [] scanStrings(int n){
            String a[]=new String [n];
            for(int i=0;i<n;i++)
            a[i]=sc.nextLine();
    
            return a;
        }
        public static class InputReader {
    
            private final InputStream stream;
            private final byte[] buf = new byte[8192];
            private int curChar, snumChars;
            private SpaceCharFilter filter;
    
            public InputReader(InputStream stream) {
                this.stream = stream;
            }
    
            public int snext() {
                if (snumChars == -1)
                    throw new InputMismatchException();
                if (curChar >= snumChars) {
                    curChar = 0;
                    try {
                        snumChars = stream.read(buf);
                    } catch (IOException e) {
                        throw new InputMismatchException();
                    }
                    if (snumChars <= 0)
                        return -1;
                }
                return buf[curChar++];
            }
    
            public int nextInt() {
                int c = snext();
                while (isSpaceChar(c)) {
                    c = snext();
                }
                int sgn = 1;
                if (c == '-') {
                    sgn = -1;
                    c = snext();
                }
                int res = 0;
                do {
                    if (c < '0' || c > '9')
                        throw new InputMismatchException();
                    res *= 10;
                    res += c - '0';
                    c = snext();
                } while (!isSpaceChar(c));
                return res * sgn;
            }
    
            public long nextLong() {
                int c = snext();
                while (isSpaceChar(c)) {
                    c = snext();
                }
                int sgn = 1;
                if (c == '-') {
                    sgn = -1;
                    c = snext();
                }
                long res = 0;
                do {
                    if (c < '0' || c > '9')
                        throw new InputMismatchException();
                    res *= 10;
                    res += c - '0';
                    c = snext();
                } while (!isSpaceChar(c));
                return res * sgn;
            }
    
            public int[] nextIntArray(int n) {
                int a[] = new int[n];
                for (int i = 0; i < n; i++) {
                    a[i] = nextInt();
                }
                return a;
            }
    
            public String readString() {
                int c = snext();
                while (isSpaceChar(c)) {
                    c = snext();
                }
                StringBuilder res = new StringBuilder();
                do {
                    res.appendCodePoint(c);
                    c = snext();
                } while (!isSpaceChar(c));
                return res.toString();
            }
    
            public String nextLine() {
                int c = snext();
                while (isSpaceChar(c))
                    c = snext();
                StringBuilder res = new StringBuilder();
                do {
                    res.appendCodePoint(c);
                    c = snext();
                } while (!isEndOfLine(c));
                return res.toString();
            }
    
            public boolean isSpaceChar(int c) {
                if (filter != null)
                    return filter.isSpaceChar(c);
                return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
            }
    
            private boolean isEndOfLine(int c) {
                return c == '\n' || c == '\r' || c == -1;
            }
    
            public interface SpaceCharFilter {
                public boolean isSpaceChar(int ch);
            }
        }
        
    }
    class SegmentTree{
        int s[],n;
        SegmentTree(int l1){
            n=l1;
            int l=(int)Math.ceil(Math.log(n)/Math.log(2));
            l=2*(int)Math.pow(2,l)-1;
            s=new int[l];
            //createSegmentTreeUtil(a, 0, 0, a.length-1);
        }
        
        int createSegmentTreeUtil(int a[],int root,int l,int r){
            if(l==r)
            s[root]=a[l];
            else
            s[root]= Compare(createSegmentTreeUtil(a, 2*root+1, l, (l+r)/2), createSegmentTreeUtil(a,2*root+2, (l+r)/2+1,r));
            return s[root];
        }
        int getValue(int gl,int gr){
            return getValueUtil(0, 0, n-1, gl, gr);
        }
        int getValueUtil(int root,int l,int r,int gl,int gr){
            if(l>=gl&&r<=gr){
                return s[root];
            }
            if(l>gr||r<gl){
                return 0;
            }
            return Compare(getValueUtil(2*root+1, l, (l+r)/2, gl, gr), getValueUtil(2*root+2, (l+r)/2+1, r, gl, gr));
        }
        void update(int p,int k){
            updateUtil(p, k,0,0,n-1);
        }
        int updateUtil(int p,int k,int root,int l,int r){
            if(l==r&&l==k){
                return s[root]=p;
            }
            else if(l>k||r<k)
            return s[root];
            else{
                return s[root]=Compare(updateUtil(p, k, 2*root+1, l, (l+r)/2), updateUtil(p, k, 2*root+2,(l+r)/2+1,r ));
            }
        }
        int Compare(int a,int b){
            return Math.max(a, b);
        }
    }
    
    
        class Pair{
            int le;
            int p;
            Pair(int leaves,int parent){
                le=leaves;
                p=parent;
            }
        }
        
        
        