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.io.*;
public class Main {

	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
		int n = Integer.parseInt(br.readLine());
		ArrayList<Integer> pos = new ArrayList<>();
		ArrayList<Integer> neg = new ArrayList<>();
		StringTokenizer st = new StringTokenizer(br.readLine());
		for(int i = 0; i < n; i++){
			int a = Integer.parseInt(st.nextToken());
			if(a > 0) pos.add(a);
			else neg.add(a);
		}
		if(pos.isEmpty()){
			Collections.sort(neg);
			Collections.reverse(neg);
			pos.add(neg.remove(0));
		}
		else if(neg.isEmpty()){
			Collections.sort(pos);
			neg.add(pos.remove(0));
		}
		int x = neg.remove(0);
		int y = pos.remove(0);
		StringBuilder sb = new StringBuilder();
		while(!pos.isEmpty()){
			int a = pos.remove(0);
			sb.append(String.format("%d %d\n", x, a));
			x = x-a;
		}
		while(!neg.isEmpty()){
			int b = neg.remove(0);
			sb.append(String.format("%d %d\n", y, b));
			y = y-b;
		}
		sb.append(String.format("%d %d\n", y, x));
		bw.write(y-x+"\n");
		bw.write(sb.toString());
		bw.flush(); bw.close();
	}

}
