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.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Scanner;
import java.util.regex.Pattern;

public class Main {

    public static void main(String[] args) {
        Scanner stdin = new Scanner(System.in);
        int n = Integer.parseInt(stdin.nextLine());
        int[] a = Pattern.compile(" ").splitAsStream(stdin.nextLine()).mapToInt(Integer::parseInt).toArray();

        Arrays.sort(a);

        List<List<Integer>> history = new ArrayList<>();
        int lo = a[0];
        int hi = a[n - 1];
        for (int i = 1; i < n - 1; i++) {
            if (a[i] > 0) {
                history.add(Arrays.asList(lo, a[i]));
                lo = lo - a[i];
            } else {
                history.add(Arrays.asList(hi, a[i]));
                hi = hi - a[i];
            }
        }
        history.add(Arrays.asList(hi, lo));

        PrintWriter out = new PrintWriter(System.out, false);
        out.println(hi - lo);
        for (List<Integer> row : history) {
            out.printf("%d %d%n", row.get(0), row.get(1));
        }
        out.flush();
    }

}