Joisino has a formula consisting of N terms: A_1 op_1 A_2 ... op_{N-1} A_N. Here, A_i is an integer, and op_i is an binary operator either `+` or `-`. Because Joisino loves large numbers, she wants to maximize the evaluated value of the formula by inserting an arbitrary number of pairs of parentheses (possibly zero) into the formula. Opening parentheses can only be inserted immediately before an integer, and closing parentheses can only be inserted immediately after an integer. It is allowed to insert any number of parentheses at a position. Your task is to write a program to find the maximum possible evaluated value of the formula after inserting an arbitrary number of pairs of parentheses.

Constraints

* 1≦N≦10^5
* 1≦A_i≦10^9
* op_i is either `+` or `-`.

Input

The input is given from Standard Input in the following format:


N
A_1 op_1 A_2 ... op_{N-1} A_N


Output

Print the maximum possible evaluated value of the formula after inserting an arbitrary number of pairs of parentheses.

Examples

Input

3
5 - 1 - 3


Output

7


Input

5
1 - 2 + 3 - 4 + 5


Output

5


Input

5
1 - 20 - 13 + 14 - 5


Output

13
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;

public class Main {
	static InputStream is;
	static PrintWriter out;
	static String INPUT = "";
	
	static void solve()
	{
		int n = ni();
		long[] a = new long[n];
		char[] op = new char[n-1];
		for(int i = 0;i < n;i++){
			a[i] = ni();
			if(i < n-1)op[i] = nc();
		}
		long[][] dp = new long[10][n+1];
		for(int i = 0;i < 10;i++){
			Arrays.fill(dp[i], Long.MIN_VALUE / 2);
		}
		dp[0][0] = 0;
		for(int i = 0;i < n;i++){
			char c = i == 0 ? '+' : op[i-1];
			for(int j = 0;j < 10;j++){
				if(c == '-'){
					if(j % 2 == 0){
						if(j >= 2){
							dp[j][i+1] = Math.max(dp[j][i+1], dp[j][i] + a[i]);
						}else{
							dp[1][i+1] = Math.max(dp[1][i+1], dp[j][i] - a[i]);
						}
					}else{
						if(j+1 < 10)dp[j+1][i+1] = Math.max(dp[j+1][i+1], dp[j][i] + a[i]);
					}
				}else{
					if(j % 2 == 0){
						dp[j][i+1] = Math.max(dp[j][i+1], dp[j][i] + a[i]);
					}else{
						dp[j-1][i+1] = Math.max(dp[j-1][i+1], dp[j][i] + a[i]);
						dp[j][i+1] = Math.max(dp[j][i+1], dp[j][i] - a[i]);
					}
				}
			}
		}
		
		long max = Long.MIN_VALUE;
		for(int j = 0;j < 10;j++){
			max = Math.max(max, dp[j][n]);
		}
		out.println(max);
	}
	
	public static void main(String[] args) throws Exception
	{
		long S = System.currentTimeMillis();
		is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		out = new PrintWriter(System.out);
		
		solve();
		out.flush();
		long G = System.currentTimeMillis();
		tr(G-S+"ms");
	}
	
	private static boolean eof()
	{
		if(lenbuf == -1)return true;
		int lptr = ptrbuf;
		while(lptr < lenbuf)if(!isSpaceChar(inbuf[lptr++]))return false;
		
		try {
			is.mark(1000);
			while(true){
				int b = is.read();
				if(b == -1){
					is.reset();
					return true;
				}else if(!isSpaceChar(b)){
					is.reset();
					return false;
				}
			}
		} catch (IOException e) {
			return true;
		}
	}
	
	private static byte[] inbuf = new byte[1024];
	static int lenbuf = 0, ptrbuf = 0;
	
	private static int readByte()
	{
		if(lenbuf == -1)throw new InputMismatchException();
		if(ptrbuf >= lenbuf){
			ptrbuf = 0;
			try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
			if(lenbuf <= 0)return -1;
		}
		return inbuf[ptrbuf++];
	}
	
	private static boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
//	private static boolean isSpaceChar(int c) { return !(c >= 32 && c <= 126); }
	private static int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
	
	private static double nd() { return Double.parseDouble(ns()); }
	private static char nc() { return (char)skip(); }
	
	private static String ns()
	{
		int b = skip();
		StringBuilder sb = new StringBuilder();
		while(!(isSpaceChar(b))){
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	
	private static char[] ns(int n)
	{
		char[] buf = new char[n];
		int b = skip(), p = 0;
		while(p < n && !(isSpaceChar(b))){
			buf[p++] = (char)b;
			b = readByte();
		}
		return n == p ? buf : Arrays.copyOf(buf, p);
	}
	
	private static char[][] nm(int n, int m)
	{
		char[][] map = new char[n][];
		for(int i = 0;i < n;i++)map[i] = ns(m);
		return map;
	}
	
	private static int[] na(int n)
	{
		int[] a = new int[n];
		for(int i = 0;i < n;i++)a[i] = ni();
		return a;
	}
	
	private static int ni()
	{
		int num = 0, b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private static long nl()
	{
		long num = 0;
		int b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private static void tr(Object... o) { if(INPUT.length() != 0)System.out.println(Arrays.deepToString(o)); }
}
