#include <iostream>
#include <fstream>
#include <queue>
#include <algorithm>
#include <vector>

using namespace std;

ifstream in("huffman.in");
ofstream out("huffman.out");

struct Nod
{
    Nod* st;
    Nod* dr;
    int val, frq;

    Nod(int val, int frq)
    {
        st = dr = NULL;
        this->val = val;
        this->frq = frq;
    }
};

struct compare
{
    bool operator()(Nod* st, Nod* dr)
    {
        return st->frq > dr->frq;
    }
};

int n,a;
priority_queue<Nod*, vector<Nod*>, compare> pq;
vector<pair<int, pair<int,int>>> dap;

int rasp;

void Parcurgere(struct Nod* Radacina, string s)
{
    if (!Radacina)
    {
        return ;
    }

    if (Radacina->val != -1)
    {
        int acm = 0;
        int j = 0;
        rasp += Radacina->frq * s.length();
        for (int i=s.length()-1; i>=0; i--)
        {
            acm = acm + (s[i] - '0') * (1<<j);
            j++;
        }
        ///cout << Radacina->val << " " << acm << "\n";
        dap.push_back({Radacina->val, {acm, s.length()}});
    }
    Parcurgere(Radacina->st, s + "0");
    Parcurgere(Radacina->dr, s + "1");
}

int main()
{
    in >> n;
    for (int i=1; i<=n; i++)
    {
        in >> a;
        pq.push(new Nod(i, a));
    }

    struct Nod *left, *right, *top;
    while(pq.size() != 1)
    {
        left = pq.top();
        pq.pop();
        right = pq.top();
        pq.pop();

        top = new Nod(-1, left->frq + right->frq);

        top->st = left;
        top->dr = right;
        pq.push(top);
    }
    Parcurgere(pq.top(), "");
    out << rasp << "\n";
    sort(dap.begin(), dap.end());

    for (auto y:dap)
    {
        out << y.second.second << " " << y.second.first << "\n";
    }
    return 0;
}