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

using namespace std;

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

const long long INF = 1LL*1000*1000*1000*1000*1000*1000;

struct Node
{
    long long freq = INF;
    int left = -1, right = -1;
};

queue<int> q1, q2;

int getmin(vector<Node> &nodes)
{
    int x1 = 0, x2 = 0;
    if(!q1.empty()){
        x1 = q1.front();
    }
    if(!q2.empty()){
        x2 = q2.front();
    }
    if(x1 == 0 || nodes[x1].freq > nodes[x2].freq){
        q2.pop();
        return x2;
    }
    q1.pop();
    return x1;
}

long long sum = 0;

void DFS(vector<Node> &nodes, vector<pair<int, long long>> &code, int level, long long currCode, int curr)
{
    if(nodes[curr].left == -1){
        code[curr].first = level;
        code[curr].second = currCode;
        sum += nodes[curr].freq * level;
        return;
    }
    DFS(nodes, code, level+1, 2*currCode, nodes[curr].left);
    DFS(nodes, code, level+1, 2*currCode+1, nodes[curr].right);
}

int main()
{
    int N;
    fin >> N;
    vector<Node> nodes(2*N+1);
    for(int i = 1; i <= N; i++){
        fin >> nodes[i].freq;
        q1.push(i);
    }
    int newNode = N+1;
    while(q1.size() + q2.size() > 1){
        int index1, index2;
        index1 = getmin(nodes);
        index2 = getmin(nodes);
        nodes[newNode].freq = nodes[index1].freq + nodes[index2].freq;
        nodes[newNode].left = index1;
        nodes[newNode].right = index2;
        q2.push(newNode);
        newNode++;
    }

    vector<pair<int, long long>> code(N+1, {1, 0});
    DFS(nodes, code, 0, 0, newNode-1);

    fout << sum << endl;
    for(int i = 1; i <= N; i++){
        fout << code[i].first << " " << code[i].second << endl;
    }
    return 0;
}