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.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        long[] ar = new long[n];
        for (int i = 0; i < n; i++) {
            ar[i] = sc.nextLong();
        }
        Arrays.sort(ar);
        if(ar[n - 1] <= 0){
            StringBuilder result = new StringBuilder();
            long curr = ar[n - 1];
            for(int i = n - 2; i >= 0; i--){
                result.append(curr);
                result.append(' ');
                result.append(ar[i]);
                result.append('\n');
                curr = curr - ar[i];
            }
            System.out.println(curr);
            System.out.println(result.toString());
        }else if(ar[0] >= 0){
            StringBuilder result = new StringBuilder();
            long curr = ar[0];
            for(int i = 1; i < n - 1; i++){
                result.append(curr);
                result.append(' ');
                result.append(ar[i]);
                result.append('\n');
                curr = curr - ar[i];
            }
            System.out.println(ar[n - 1] - curr);
            result.append(ar[n - 1]);
            result.append(' ');
            result.append(curr);
            System.out.println(result.toString());
        }else{
            int index = 1;
            long curr = ar[n - 1];
            StringBuilder result = new StringBuilder();
            while(index < n && ar[index] <= 0){
                result.append(curr);
                result.append(' ');
                result.append(ar[index]);
                result.append('\n');
                curr = curr - ar[index];
                index += 1;
            }
            long currAlt = ar[0];
            for(int i = index; i < n - 1; i++){
                result.append(currAlt);
                result.append(' ');
                result.append(ar[i]);
                result.append('\n');
                currAlt -= ar[i];
            }
            System.out.println(curr - currAlt);
            result.append(curr);
            result.append(' ');
            result.append(currAlt);
            System.out.println(result.toString());
        }
    }
}
