#include <iostream>
#include <fstream>
#include <queue>
#include <string>
#define NMAX 1000005

using namespace std;

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

//queue< long > Q, newQ;
long Q[NMAX], newQ[NMAX], sizeQ = 0, sizeNewQ = 0, startQ = 0, startNewQ = 0;


struct Node 
{
    long long value;
    long next[2];
}node[2*NMAX];

long n, k, root, level[2 * NMAX];
long long cod[2 * NMAX], lg;

void calcLevel(long k, long nivel, long long c)
{
    level[k] = nivel;
    cod[k] = c;
    if (node[k].next[0] != 0)
    {
        calcLevel(node[k].next[0], nivel + 1, 2 * c);
        calcLevel(node[k].next[1], nivel + 1, 2 * c + 1);
    }
}

void solve()
{
    k = n;

    //while (Q.size() + newQ.size() >= 2)
    while (sizeQ + sizeNewQ - startQ - startNewQ >= 2)
    {
        long x1, x2;

        //if (!newQ.empty() && (Q.empty() || node[Q.front()].value >  node[newQ.front()].value))
        if (sizeNewQ > startNewQ && (sizeQ <= startQ || node[Q[startQ]].value > node[newQ[startNewQ]].value))
        {
            //x1 = newQ.front();
            x1 = newQ[startNewQ++];
            //newQ.pop();
        }
        else
        {
            //x1 = Q.front();
            //Q.pop();
            x1 = Q[startQ++];
        }

        //if (!newQ.empty() && (Q.empty() || node[Q.front()].value >  node[newQ.front()].value))
        if (sizeNewQ > startNewQ && (sizeQ <= startQ || node[Q[startQ]].value > node[newQ[startNewQ]].value))
        {
            x2 = newQ[startNewQ++];
        }
        else
        {
            x2 = Q[startQ++];
        }

        k++;
        node[k].value = node[x1].value + node[x2].value;
        lg += node[k].value;
        node[k].next[0] = x1;
        node[k].next[1] = x2;
        //newQ.push(k);
        newQ[sizeNewQ++] = k;
    }
    root = k;
}

void read()
{
    f >> n;
    for (int i = 1; i <= n; i++)
    {
        f >> node[i].value;
        node[i].next[0] = node[i].next[1] = 0;
        //Q.push(i);
        Q[i] = i;
    }
    startQ = 1;
    sizeQ = n + 1;
    startNewQ = 1;
    sizeNewQ = 1;
}

int main()
{
    read();
    solve();
    calcLevel(root, 0, 0);

    long long sum = 0;
    //for (int i = 1; i <= n; i++)
        //sum += node[i].value * level[i];
    g << lg <<'\n';

    for (int i = 1; i <= n; i++)
        g << level[i] << ' ' << cod[i] << '\n';
    return 0;
}