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[] nums = new int[N];
        for (int i = 0; i < N; i++) nums[i]=sc.nextInt();

        //sort
        Arrays.sort(nums);

        StringBuilder sb = new StringBuilder();
        // + Max  - min  and middle |abs|
        int max =nums[nums.length-1];
        int min =nums[0];
        int ans = min;
        for (int i = 1; i <= nums.length-2 ; i++) {// minus all positive except max
            if(nums[i]>=0){
                sb.append(ans+" "+nums[i]+"\n");
                ans = ans - nums[i];
            }
        }
        sb.append(max+" "+ans+"\n");
        ans = max - ans;
        for (int i = 1; i <= nums.length-2 ; i++) {// minus all positive except max
            if(nums[i]<0){
                sb.append(ans+" "+nums[i]+"\n");
                ans = ans - nums[i];
            }
        }

        System.out.println(ans);
        System.out.println(sb.toString());
    }

}
