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.*;
import java.math.*;
import java.util.*;
import java.util.stream.*;

public class Main {

	static final long INF = Long.MAX_VALUE / 10;
	
	void submit() {
		int n = nextInt();
		long[] a = new long[n];
		boolean[] plus = new boolean[n - 1];
		for (int i = 0; i < n; i++) {
			a[i] = nextInt();
			if (i != n - 1) {
				plus[i] = nextToken().equals("+");
			}
		}
		
		long[] dp = new long[C];
		Arrays.fill(dp, -INF);
		dp[0] = a[0];
		
		for (int i = 1; i < n; i++) {
			long[] nxt = new long[C];
			Arrays.fill(nxt, -INF);
			boolean sgn = plus[i - 1];
			long x = a[i];
			
			for (int was = 0; was < C; was++) {
				int nowMax = Math.min(was + (sgn ? 0 : 1), C - 1);
				long delta = (nowMax % 2 == 0) ? x : -x;
				for (int j = 0; j <= nowMax; j++) {
					nxt[j] = Math.max(nxt[j], dp[was] + delta);
				}
			}
			dp = nxt;
		}
		
		out.println(Arrays.stream(dp).max().getAsLong());
	}

	void test() {

	}

	void stress() {
		for (int tst = 0;; tst++) {
			if (false) {
				throw new AssertionError();
			}
			System.err.println(tst);
		}
	}

	Main() throws IOException {
		is = System.in;
		out = new PrintWriter(System.out);
		submit();
		// stress();
		// test();
		out.close();
	}

	static final Random rng = new Random();
	static final int C = 5;

	static int rand(int l, int r) {
		return l + rng.nextInt(r - l + 1);
	}

	public static void main(String[] args) throws IOException {
		new Main();
	}

	private InputStream is;
	PrintWriter out;

	private byte[] buf = new byte[1 << 14];
	private int bufSz = 0, bufPtr = 0;

	private int readByte() {
		if (bufSz == -1)
			throw new RuntimeException("Reading past EOF");
		if (bufPtr >= bufSz) {
			bufPtr = 0;
			try {
				bufSz = is.read(buf);
			} catch (IOException e) {
				throw new RuntimeException(e);
			}
			if (bufSz <= 0)
				return -1;
		}
		return buf[bufPtr++];
	}

	private boolean isTrash(int c) {
		return c < 33 || c > 126;
	}

	private int skip() {
		int b;
		while ((b = readByte()) != -1 && isTrash(b))
			;
		return b;
	}

	String nextToken() {
		int b = skip();
		StringBuilder sb = new StringBuilder();
		while (!isTrash(b)) {
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}

	String nextString() {
		int b = readByte();
		StringBuilder sb = new StringBuilder();
		while (!isTrash(b) || b == ' ') {
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}

	double nextDouble() {
		return Double.parseDouble(nextToken());
	}

	char nextChar() {
		return (char) skip();
	}

	int nextInt() {
		int ret = 0;
		int b = skip();
		if (b != '-' && (b < '0' || b > '9')) {
			throw new InputMismatchException();
		}
		boolean neg = false;
		if (b == '-') {
			neg = true;
			b = readByte();
		}
		while (true) {
			if (b >= '0' && b <= '9') {
				ret = ret * 10 + (b - '0');
			} else {
				if (b != -1 && !isTrash(b)) {
					throw new InputMismatchException();
				}
				return neg ? -ret : ret;
			}
			b = readByte();
		}
	}

	long nextLong() {
		long ret = 0;
		int b = skip();
		if (b != '-' && (b < '0' || b > '9')) {
			throw new InputMismatchException();
		}
		boolean neg = false;
		if (b == '-') {
			neg = true;
			b = readByte();
		}
		while (true) {
			if (b >= '0' && b <= '9') {
				ret = ret * 10 + (b - '0');
			} else {
				if (b != -1 && !isTrash(b)) {
					throw new InputMismatchException();
				}
				return neg ? -ret : ret;
			}
			b = readByte();
		}
	}
}
