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];
        long sum = 0;
        int plus = 0;
        for(int i = 0; i < N; i++){
            a[i] = sc.nextInt();
            if(a[i]>=0) plus++;
            sum += Math.abs(a[i]);
        }
        sc.close();

        Arrays.sort(a);
        long ans = sum;
        if(plus == N)
            ans -= 2*a[0];
        else if(plus == 0)
            ans += 2*a[N-1];
        System.out.println(ans);
        if(plus == N) plus--;
        if(plus == 0) plus++;
        int xy = a[N-1];
        for(int i = 1; i < N-plus; i++){
            System.out.println(xy + " " + a[i]);
            xy = xy - a[i];
        }
        int yx = a[0];
        for(int i = N-2; i >= N-plus; i--){
            System.out.println(yx + " " + a[i]);
            yx = yx - a[i];
        }
        System.out.println(xy + " " + yx);
    }
}