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.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;
import java.util.NoSuchElementException;

public class Main {

	static PrintWriter out;
	static InputReader ir;
	static boolean debug = false;

	static void solve() {
		int n = ir.nextInt();
		int[] a = new int[n];
		char[] op = new char[n - 1];
		for (int i = 0; i < n - 1; i++) {
			a[i] = ir.nextInt();
			op[i] = ir.next().charAt(0);
		}
		a[n - 1] = ir.nextInt();
		long loss = 0;
		long mi = (long) 1e18;
		for (int i = 0; i < n - 1; i++) {
			if (op[i] == '-') {
				loss += a[i + 1];
				long t = 0;
				i++;
				while (i < n - 1 && op[i] == '+')
					t += a[++i];
				i--;
				mi = Math.min(mi, loss + t);
			}
		}
		long sum = 0;
		for (int i = 0; i < n; i++)
			sum += a[i];
		if (mi == (long) 1e18)
			out.println(sum);
		else
			out.println(sum - mi * 2);
	}

	public static void main(String[] args) {
		ir = new InputReader(System.in);
		out = new PrintWriter(System.out);
		solve();
		out.flush();
	}

	static class InputReader {

		private InputStream in;
		private byte[] buffer = new byte[1024];
		private int curbuf;
		private int lenbuf;

		public InputReader(InputStream in) {
			this.in = in;
			this.curbuf = this.lenbuf = 0;
		}

		public boolean hasNextByte() {
			if (curbuf >= lenbuf) {
				curbuf = 0;
				try {
					lenbuf = in.read(buffer);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (lenbuf <= 0)
					return false;
			}
			return true;
		}

		private int readByte() {
			if (hasNextByte())
				return buffer[curbuf++];
			else
				return -1;
		}

		private boolean isSpaceChar(int c) {
			return !(c >= 33 && c <= 126);
		}

		private void skip() {
			while (hasNextByte() && isSpaceChar(buffer[curbuf]))
				curbuf++;
		}

		public boolean hasNext() {
			skip();
			return hasNextByte();
		}

		public String next() {
			if (!hasNext())
				throw new NoSuchElementException();
			StringBuilder sb = new StringBuilder();
			int b = readByte();
			while (!isSpaceChar(b)) {
				sb.appendCodePoint(b);
				b = readByte();
			}
			return sb.toString();
		}

		public int nextInt() {
			if (!hasNext())
				throw new NoSuchElementException();
			int c = readByte();
			while (isSpaceChar(c))
				c = readByte();
			boolean minus = false;
			if (c == '-') {
				minus = true;
				c = readByte();
			}
			int res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res = res * 10 + c - '0';
				c = readByte();
			} while (!isSpaceChar(c));
			return (minus) ? -res : res;
		}

		public long nextLong() {
			if (!hasNext())
				throw new NoSuchElementException();
			int c = readByte();
			while (isSpaceChar(c))
				c = readByte();
			boolean minus = false;
			if (c == '-') {
				minus = true;
				c = readByte();
			}
			long res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res = res * 10 + c - '0';
				c = readByte();
			} while (!isSpaceChar(c));
			return (minus) ? -res : res;
		}

		public double nextDouble() {
			return Double.parseDouble(next());
		}

		public int[] nextIntArray(int n) {
			int[] a = new int[n];
			for (int i = 0; i < n; i++)
				a[i] = nextInt();
			return a;
		}

		public long[] nextLongArray(int n) {
			long[] a = new long[n];
			for (int i = 0; i < n; i++)
				a[i] = nextLong();
			return a;
		}

		public char[][] nextCharMap(int n, int m) {
			char[][] map = new char[n][m];
			for (int i = 0; i < n; i++)
				map[i] = next().toCharArray();
			return map;
		}
	}

	static void tr(Object... o) {
		if (debug)
			out.println(Arrays.deepToString(o));
	}
}
