There are N integers, A_1, A_2, ..., A_N, written on a blackboard.

We will repeat the following operation N-1 times so that we have only one integer on the blackboard.

* Choose two integers x and y on the blackboard and erase these two integers. Then, write a new integer x-y.



Find the maximum possible value of the final integer on the blackboard and a sequence of operations that maximizes the final integer.

Constraints

* 2 \leq N \leq 10^5
* -10^4 \leq A_i \leq 10^4
* All values in input are integers.

Input

Input is given from Standard Input in the following format:


N
A_1 A_2 ... A_N


Output

Print the maximum possible value M of the final integer on the blackboard, and a sequence of operations x_i, y_i that maximizes the final integer, in the format below.

Here x_i and y_i represent the integers x and y chosen in the i-th operation, respectively.

If there are multiple sequences of operations that maximize the final integer, any of them will be accepted.


M
x_1 y_1
:
x_{N-1} y_{N-1}

Output

Print the maximum possible value M of the final integer on the blackboard, and a sequence of operations x_i, y_i that maximizes the final integer, in the format below.

Here x_i and y_i represent the integers x and y chosen in the i-th operation, respectively.

If there are multiple sequences of operations that maximize the final integer, any of them will be accepted.


M
x_1 y_1
:
x_{N-1} y_{N-1}

Examples

Input

3
1 -1 2


Output

4
-1 1
2 -2


Input

3
1 1 1


Output

1
1 1
1 0

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import java.util.StringTokenizer;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

public class Main {
    public static void main(final String[] args) {
        final FastScanner scanner = new FastScanner(System.in);
        final int n = scanner.nextInt();
        final List<Integer> list = IntStream.range(0, n)
                .mapToObj(i -> scanner.nextInt())
                .sorted()
                .collect(Collectors.toList());

        final List<String> answer = new ArrayList<>();
        final int first = list.get(0);
        final int last = list.get(list.size() - 1);
        int tmp;
        if (first >= 0) {
            tmp = first;
            for (int i = 1; i < list.size() - 1; i++) {
                answer.add(tmp + " " + list.get(i));
                tmp -= list.get(i);
            }
            answer.add(last + " " + tmp);
            tmp = last - tmp;
        } else if (last <= 0) {
            tmp = last;
            for (int i = 0; i < list.size() - 1; i++) {
                answer.add(tmp + " " + list.get(i));
                tmp -= list.get(i);
            }
        } else {
            tmp = first;
            int tmp2 = last;
            for (int i = 1; i < list.size() - 1; i++) {
                final int current = list.get(i);
                if (current < 0) {
                    answer.add(tmp2 + " " + current);
                    tmp2 -= current;
                } else {
                    answer.add(tmp + " " + current);
                    tmp -= current;
                }
            }
            answer.add(tmp2 + " " + tmp);
            tmp = tmp2 - tmp;
        }

        System.out.println(tmp);
        answer.forEach(System.out::println);
    }

    private static class FastScanner {
        private final BufferedReader reader;
        private StringTokenizer tokenizer;

        FastScanner(final InputStream in) {
            reader = new BufferedReader(new InputStreamReader(in));
            tokenizer = null;
        }

        String next() {
            if (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }
    }
}
    