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.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve();
    }
    public void solve() {
        Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int N = scan.nextInt();
        long[] a = new long[N];
        long sum = 0;
        int count_negative = 0;
        for (int i = 0; i < N; i++) {
            a[i] = scan.nextLong();
            sum += a[i];
            if (a[i] < 0) {
                count_negative += 1;
            }
        }
        int count_positive = N - count_negative;
        Arrays.sort(a);
        if (count_negative == 0) {
            count_negative = 1;
            count_positive -= 1;
        }
        if (count_positive == 0) {
            count_negative -= 1;
            count_positive = 1;
        }
        long x = a[0];
        for (int i = count_negative; i < N - 1; i++) {
            x = x - a[i];
        }
        long y = a[N-1];
        for (int i = 1; i < count_negative; i++) {
            y = y - a[i];
        }
        long answer = y - x;
        System.out.println(answer);
        x = a[0];
        for (int i = count_negative; i < N - 1; i++) {
            System.out.println(x + " " + a[i]);
            x = x - a[i];
        }
        y = a[N-1];
        for (int i = 1; i < count_negative; i++) {
            System.out.println(y + " " + a[i]);
            y = y - a[i];
        }
        System.out.println(y + " " + x);
    }
}