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.util.Arrays;
import java.util.NoSuchElementException;

public class Main {

	public static void main(String[] args) {
		FastScanner sc = new FastScanner();
		int N = sc.nextInt();

		long[] A = new long[N + 1];
		long[] B = new long[N + 1];
		boolean[] p = new boolean[N + 1];
		p[1] = true;

		for (int i = 1; i <= N; i++) {
			if (i > 1) {
				p[i] = sc.next().equals("+");
			}
			A[i] = sc.nextLong();

			B[i] = A[i] * (p[i] ? 1 : -1);
		}

		long[][] dp = new long[N + 1][3];
		for (long[] v : dp) Arrays.fill(v, Long.MIN_VALUE / 2);
		dp[0][0] = 0;

		for (int i = 0; i < N; i++) {
			if (p[i + 1]) {
				dp[i + 1][0] = Math.max(dp[i + 1][0], dp[i][0] + A[i + 1]);
				dp[i + 1][0] = Math.max(dp[i + 1][0], dp[i][1] + A[i + 1]);
				dp[i + 1][0] = Math.max(dp[i + 1][0], dp[i][2] + A[i + 1]);

				dp[i + 1][1] = Math.max(dp[i + 1][1], dp[i][1] - A[i + 1]);
				dp[i + 1][1] = Math.max(dp[i + 1][1], dp[i][2] - A[i + 1]);

				dp[i + 1][2] = Math.max(dp[i + 1][2], dp[i][2] + A[i + 1]);

			} else {
				dp[i + 1][0] = Math.max(dp[i + 1][0], dp[i][0] - A[i + 1]);
				dp[i + 1][0] = Math.max(dp[i + 1][0], dp[i][1] - A[i + 1]);
				dp[i + 1][0] = Math.max(dp[i + 1][0], dp[i][2] - A[i + 1]);

				dp[i + 1][1] = Math.max(dp[i + 1][1], dp[i][0] - A[i + 1]);
				dp[i + 1][1] = Math.max(dp[i + 1][1], dp[i][1] + A[i + 1]);
				dp[i + 1][1] = Math.max(dp[i + 1][1], dp[i][2] + A[i + 1]);

				dp[i + 1][2] = Math.max(dp[i + 1][2], dp[i][1] + A[i + 1]);
				dp[i + 1][2] = Math.max(dp[i + 1][2], dp[i][2] + A[i + 1]);
			}
		}
		long max = Long.MIN_VALUE / 2;
		max = Math.max(dp[N][0], max);
		max = Math.max(dp[N][1], max);
		max = Math.max(dp[N][2], max);

		System.out.println(max);
	}
}

class FastScanner {
	public static String debug = null;

	private final InputStream in = System.in;
	private int ptr = 0;
	private int buflen = 0;
	private byte[] buffer = new byte[1024];
	private boolean eos = false;

	private boolean hasNextByte() {
		if (ptr < buflen) {
			return true;
		} else {
			ptr = 0;
			try {
				if (debug != null) {
					buflen = debug.length();
					buffer = debug.getBytes();
					debug = "";
					eos = true;
				} else {
					buflen = in.read(buffer);
				}
			} catch (IOException e) {
				e.printStackTrace();
			}
			if (buflen < 0) {
				eos = true;
				return false;
			} else if (buflen == 0) {
				return false;
			}
		}
		return true;
	}

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

	private static boolean isPrintableChar(int c) {
		return 33 <= c && c <= 126;
	}

	private void skipUnprintable() {
		while (hasNextByte() && !isPrintableChar(buffer[ptr]))
			ptr++;
	}

	public boolean isEOS() {
		return this.eos;
	}

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

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

	public long nextLong() {
		if (!hasNext())
			throw new NoSuchElementException();
		long n = 0;
		boolean minus = false;
		int b = readByte();
		if (b == '-') {
			minus = true;
			b = readByte();
		}
		if (b < '0' || '9' < b) {
			throw new NumberFormatException();
		}
		while (true) {
			if ('0' <= b && b <= '9') {
				n *= 10;
				n += b - '0';
			} else if (b == -1 || !isPrintableChar(b)) {
				return minus ? -n : n;
			} else {
				throw new NumberFormatException();
			}
			b = readByte();
		}
	}

	public int nextInt() {
		return (int) nextLong();
	}

	public long[] nextLongList(int n) {
		return nextLongTable(1, n)[0];
	}

	public int[] nextIntList(int n) {
		return nextIntTable(1, n)[0];
	}

	public long[][] nextLongTable(int n, int m) {
		long[][] ret = new long[n][m];
		for (int i = 0; i < n; i++) {
			for (int j = 0; j < m; j++) {
				ret[i][j] = nextLong();
			}
		}
		return ret;
	}

	public int[][] nextIntTable(int n, int m) {
		int[][] ret = new int[n][m];
		for (int i = 0; i < n; i++) {
			for (int j = 0; j < m; j++) {
				ret[i][j] = nextInt();
			}
		}
		return ret;
	}
}