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 sc = new Scanner(System.in);
		int N = sc.nextInt();
		int[] A = new int[N];
		boolean allplus = true;
		boolean allminus = true;
		long total = 0;
		for(int i = 0; i < N; i++) {
			A[i] = sc.nextInt();
			if(A[i] <= 0)
				allplus = false;
			if(A[i] >= 0)
				allminus = false;
			total += Math.abs(A[i]);
		}
		Arrays.sort(A);
		StringBuilder ans = new StringBuilder();
		if(allplus) {
			int a = A[0];
			System.out.println(total-A[0]*2);
			for(int i = 1; i < N-1; i++) {
				ans.append(a + " " + A[i] + "\n");
				a -= A[i];
			}
			ans.append(A[N-1] + " " + a + "\n");
			System.out.print(ans);
			return;
		}
		if(allminus) {
			int a = A[N-1];
			System.out.println(total+A[N-1]*2);
			for(int i = 0; i < N-1; i++) {
				ans.append(a + " " + A[i] + "\n");
				a -= A[i];
			}
			System.out.print(ans);
			return;
		}
		int a = A[0];
		int minusnum = 0;
		System.out.println(total);
		for(int i = N-2; i >= 0; i--) {
			if(A[i] > 0) {
				ans.append(a + " " + A[i] + "\n");
				a -= A[i];
			}
			else {
				minusnum = i;
				break;
			}
		}
		int b = A[N-1];
		ans.append(b + " " + a + "\n");
		b -= a;
		for(int i = 1; i <= minusnum; i++) {
			ans.append(b + " " + A[i] + "\n");
			b -= A[i];
		}		
		System.out.print(ans);

	}

}