#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
using namespace std;

int main()
{
    int n;cin>>n;
    vector<int> a(n);
    priority_queue<int,vector<int>,greater<int>> pq;
    for(int &x:a){cin>>x;pq.push(x);};
    vector<pair<int,int>> ans;
    int sum=0;
    while(pq.size()>1)
        {
        int n1,n2;
        n1=pq.top();pq.pop();
        n2=pq.top();pq.pop();
        ans.push_back({n1+n2,n1});
        sum+=n1+n2;
        pq.push(n1+n2);
        }
    cout<<sum<<"\n";
    reverse(ans.begin(),ans.end());
    for(auto [x,y]:ans)cout<<x<<" "<<y<<"\n";
    return 0;
}