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[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		Integer[] A = new Integer[N];
		int sum=0;
		int all_plus=0;
		int all_minus=0;
		for (int i=0;i<N;i++) {
			A[i]=sc.nextInt();
			sum+=Math.abs(A[i]);
		}
		Arrays.sort(A);

		if (N==2) {
			System.out.println(A[1]-A[0]);
			System.out.print(A[1]);
			System.out.print(" ");
			System.out.println(A[0]);
		} else {
			Queue<Integer> plus = new ArrayDeque<Integer>();
			Queue<Integer> minus = new ArrayDeque<Integer>();
			List<Integer> list = new LinkedList<Integer>();
			for (int i=0;i<N;i++) {
				if (A[i]>0) {
					plus.add(A[i]);
					all_plus=1;
				} else {
					list.add(A[i]);
					all_minus=1;
				}
			}
			Collections.reverse(list);
			List<Integer> list_2 = new ArrayList<Integer>(list);
			for (int i=0;i<list.size();i++) {
				minus.add(list_2.get(i));
			}
			if (all_plus==0) {
				sum+=2*minus.peek();
			} else if (all_minus==0) {
				sum-=2*plus.peek();
			}
			System.out.println(sum);

			if (plus.isEmpty()) {
				int tmp=minus.remove();
				int tmp_2=minus.remove();
				System.out.print(tmp);
				System.out.print(" ");
				System.out.println(tmp_2);
				plus.add(tmp-tmp_2);
			}
			if (minus.isEmpty()) {
				int tmp=plus.remove();
				int tmp_2=plus.remove();
				System.out.print(tmp);
				System.out.print(" ");
				System.out.println(tmp_2);
				minus.add(tmp-tmp_2);
			}

			while (plus.size()>1) {
				int tmp=plus.remove();
				int tmp_2=minus.remove();
				System.out.print(tmp_2);
				System.out.print(" ");
				System.out.println(tmp);
				minus.add(tmp_2-tmp);
			}

			while (!minus.isEmpty()) {
				int tmp=plus.remove();
				int tmp_2=minus.remove();
				System.out.print(tmp);
				System.out.print(" ");
				System.out.println(tmp_2);
				plus.add(tmp-tmp_2);
			}
		}
	}
}