#include <bits/stdc++.h>

#define llg long long
#define int_pair std::pair <llg, int>

class HuffmanCoding {
public:
    std::vector <int> lg;
    std::vector <llg> bits;
    HuffmanCoding(const std::vector <int>& frequencies) {
        lg.resize(frequencies.size()), bits.resize(frequencies.size());
        buildTree(frequencies);
        DFS(tree.size()-1);
    }

private:
    void buildTree(const std::vector <int>& frequencies) {
        std::queue <int> queue1, queue2;
        tree.resize(frequencies.size());
        for (int i=0; i<tree.size(); ++i)
            tree[i].rang = frequencies[i], queue1.push(i);

        int min[2];
        while (queue1.size() + queue2.size() >= 2) {
            for (int i=0; i<2; ++i) {
                if (queue1.empty()) min[i] = queue2.front(), queue2.pop();
                else if (queue2.empty()) min[i] = queue1.front(), queue1.pop();
                else if (tree[queue1.front()].rang < tree[queue2.front()].rang) min[i] = queue1.front(), queue1.pop();
                else min[i] = queue2.front(), queue2.pop();
            }   tree.push_back(node(tree[min[0]].rang + tree[min[1]].rang, min[0], min[1]));
            queue2.push(tree.size()-1);
        }
    }

    void DFS(int vertex, llg encoding = 0, int lvl = 0) {
        if (tree[vertex].son[0] == -1 && tree[vertex].son[1] == -1)
            {lg[vertex] = lvl, bits[vertex] = encoding; return;}

        for (int i=0; i<2; ++i)
            if (tree[vertex].son[i] != -1)
                DFS(tree[vertex].son[i], 2*encoding + i, lvl+1);
    }
protected:
    struct node {
        node(llg rang = 0, int son0 = -1, int son1 = -1) : rang(rang) {son[0] = son0; son[1] = son1;}
        llg rang; int son[2];
    };
public:
    std::vector <node> tree;
};

const int MAXN = 1e6 + 5;
const llg INF  = 1e18;

int N;
std::vector <int> freq;

std::ifstream input ("huffman.in");
std::ofstream output("huffman.out");

void readInput() {
    input >> N;
    freq.resize(N);
    for (auto &it:freq)
        input >> it;
}

void solveInput() {
    HuffmanCoding huffman(freq);

    llg sum = 0;
    for (int i=0; i<huffman.tree.size(); ++i)
        sum += huffman.tree[i].rang;
    for (auto &it:freq)
        sum -= it;
    output << sum << '\n';

    for (int i=0; i<N; ++i)
        output << huffman.lg[i] << ' ' << huffman.bits[i] << '\n';
}

int main()
{
    readInput();
    solveInput();

    return 0;
}