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];
        int p = 0;
        int m = 0;
        for (int i = 0; i < n; i++) {
            a[i] = sc.nextInt();
            if(a[i] < 0) m++;
            else p++;
        }
        Arrays.sort(a);
        StringBuilder sb = new StringBuilder();
        int t;
        if(p == 0){
            t = a[n-1];
            for (int i = 0; i < n-1; i++) {
                sb.append(t + " " + a[i] + "\n");
                t -= a[i];
            }
        }else if(m == 0){
            if(2 < p){
                t = a[0];
                for (int i = 1; i < n-1; i++) {
                    sb.append(t + " " + a[i] + "\n");
                    t -= a[i];
                }
                sb.append(a[n-1] + " " + t + "\n");
                t = a[n-1] - t;
            }else{
                sb.append(a[n-1] + " " + a[n-2] + "\n");
                t = a[n-1] - a[n-2];
            }
        }else if(p == 1){
            t = a[n-1];
            for (int i = 0; i < n-1; i++) {
                sb.append(t + " " + a[i] + "\n");
                t -= a[i];
            }
        }else{
            t = a[0];
            for (int i = m; i < n-1; i++) {
                sb.append(t + " " + a[i] + "\n");
                t -= a[i];
            }
            sb.append(a[n-1] + " " + t + "\n");
            t = a[n-1] - t;
            for (int i = 1; i < m; i++) {
                sb.append(t + " " + a[i] + "\n");
                t -= a[i];
            }
        }
        System.out.println(t);
        System.out.print(sb.toString());
        sc.close();

    }

}
