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.*;
import java.lang.*;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		long[] a = new long[n];
		for (int i = 0; i < n; i++) {
			a[i] = sc.nextLong();
		}
		Arrays.sort(a);
		long sum1 = a[n - 1];
		long sum2 = a[0];
		int i = 1;
		while (a[i] <= 0 && i < n - 1) {
			sum1 -= a[i];
			i++;
		}
		while (i < n - 1) {
			sum2 -= a[i];
			i++;
		}
		System.out.println(sum1 - sum2);
		sum1 = a[n - 1];
		sum2 = a[0];
		i = 1;
		while (a[i] <= 0 && i < n - 1) {
			System.out.println(sum1 + " " + a[i]);
			sum1 -= a[i];
			i++;
		}
		while (i < n - 1) {
			System.out.println(sum2 + " " + a[i]);
			sum2 -= a[i];
			i++;
		}
		System.out.println(sum1 + " " + sum2);
	}
}

