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.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int[] a = new int[n];
        for(int i=0; i<n; i++) {
            a[i] = in.nextInt();
        }
        Arrays.sort(a);
        LinkedList<Integer> l = new LinkedList<>();
        for(int i=0; i<n; i++) {
            l.add(a[i]);
        }
        int min = l.pollFirst();
        int max = l.pollLast();
        List<Tuple> operations = new ArrayList<>();
        int m = min;
        while(!l.isEmpty()) {
            Tuple t = new Tuple();
            int next = l.pollLast();
            if(next > 0) {
                t.x = m;
                t.y = next;
                m -= next;
            }
            else {
                t.x = max;
                t.y = next;
                max = max - next;
            }
            operations.add(t);
        }
        Tuple t = new Tuple();
        t.x = max;
        t.y = m;
        operations.add(t);
        m = max - m;
        System.out.println(m);
        for(int i=0; i<operations.size(); i++) {
            Tuple t2 = operations.get(i);
            System.out.print(t2.x);
            System.out.print(" ");
            System.out.println(t2.y);
        }
    }
}
class Tuple {
    int x;
    int y;
}