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.*;

class Main{
	public static void main(String[] $){
		Scanner s=new Scanner(System.in);

		int n=s.nextInt();
		int[]a=new int[n];
		for(int i=0;i<n;++i)
			a[i]=s.nextInt();
		Arrays.sort(a);

		ArrayList<String>r=new ArrayList<>();

		for(int i=n-2;i>0;--i) {
			if(a[i]<=0)
				break;
			r.add(a[0]+" "+a[i]);
			a[0]-=a[i];
			a[i]=Integer.MAX_VALUE;
		}
		for(int i=0;i<n-1;++i) {
			if(a[i]==Integer.MAX_VALUE)
				break;
			r.add(a[n-1]+" "+a[i]);
			a[n-1]-=a[i];
		}
		System.out.println(a[n-1]);
		r.forEach(System.out::println);
	}
}