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>
typedef long long ll;
using namespace std;
const ll N=1e5+5;
ll n,a[N];
int main(){
    cin.tie(NULL); cout.tie(NULL);
    ios_base:: sync_with_stdio(false);
    cin>>n;
    for(ll i=0;i<n;i++)cin>>a[i];
    sort(a,a+n,greater<ll>());
    vector< pair<ll,ll> > ans;
    for(ll i=1;i<n-1;i++){
        if(a[i]>=0)ans.push_back({a[n-1],a[i]}),a[n-1]-=a[i];
        else ans.push_back({a[0],a[i]}),a[0]-=a[i];
    }
    ans.push_back({a[0],a[n-1]});
    cout<<a[0]-a[n-1]<<"\n";
    for(auto &ele:ans)cout<<ele.first<<" "<<ele.second<<"\n";
}