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
#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)
#define all(a) (a).begin(),(a).end()
#define ll long long
int main(){
  int N;
  cin>>N;
  vector<int> A(N);
  rep(i,N) cin>>A[i];
  sort(all(A));
  int tmp=A[N-1],tmp2=A[0];
  vector<pair<int,int>> P(N-1); 
  rep(i,N-2){
    if(A[N-2-i]<0){
      P[i]=make_pair(tmp,A[N-2-i]);
      tmp-=A[N-2-i];
    }else{
      P[i]=make_pair(tmp2,A[N-2-i]);
      tmp2-=A[N-2-i];
    }
  }
  P[N-2]=make_pair(tmp,tmp2);
  cout<<tmp-tmp2<<endl;
  rep(i,N-1) cout<<P[i].first<<" "<<P[i].second<<endl;
}