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.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		int N = Integer.parseInt(sc.next());
		ArrayList<Integer> integers=new ArrayList<Integer>(N);
		for(int i=0;i<N;i++) {
			integers.add(Integer.parseInt(sc.next()));
		}
		Collections.sort(integers, Comparator.reverseOrder());
		
		int max=integers.get(0);
		int min=integers.get(integers.size()-1);
        integers.remove(0);
		integers.remove(integers.size()-1);		
		ArrayList<Integer> anser=new ArrayList<Integer>(2*N);
		
		for(int num:integers) {
			if(num>0) {
				anser.add(min);
				anser.add(num);
				min=min-num;
			}else {
				anser.add(max);
				anser.add(num);
				max=max-num;
			}
		}
		System.out.println(max-min);
		
		for(int i=0;i<N-2;i++) {
			System.out.println(anser.get(2*i)+" "+anser.get(2*i+1));
		}
		System.out.println(max+" "+min);
		sc.close();
	}
}
