#include <fstream>

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

struct Node { long long val; long leftPos, rightPos;};

constexpr auto INF = 1LL * 1000000000 * 1000000000;

Node nodes[2000200];
long long unsigned len[1000200];
long long unsigned code[1000200];

long getNodePosWithMinValue(Node nodes[], long& i, long& qFront, long qEnd, long n)
{
    long pos = -1;
    if(nodes[i].val < nodes[qFront].val)
    {
        pos = i;
        ++i;
    }
    else
    {
        pos = qFront;
        ++qFront;
    }

    return pos;
}

long Huffman(Node nodes[], long n)
{
    long i=0;
    long qFront = n + 1;
    long qEnd = n + 1;

    while(!(nodes[i].val == INF && nodes[qFront + 1].val == INF))
    {
        long leftPos = getNodePosWithMinValue(nodes, i, qFront, qEnd, n);
        long rightPos = getNodePosWithMinValue(nodes, i, qFront, qEnd, n);

        nodes[qEnd].val = nodes[leftPos].val + nodes[rightPos].val;
        nodes[qEnd].leftPos = leftPos;
        nodes[qEnd].rightPos = rightPos;

        ++qEnd;
    }

    return qFront;
}

void DepthFirst(Node nodes[], long pos, long long int val = 0, long length = 0)
{
    if (nodes[pos].leftPos != -1)
    {
        DepthFirst(nodes, nodes[pos].leftPos, val * 2, length + 1);
        DepthFirst(nodes, nodes[pos].rightPos, val * 2 + 1, length + 1);
    }
    else
    {
        len[pos] = length;
        code[pos] = val;
    }
}

int main()
{
    long n;
    f >> n;

    for(long i = 0; i < n; ++i)
    {
        f >> nodes[i].val;
        nodes[i].leftPos = -1;
        nodes[i].rightPos = -1;
    }

    for(long i = n; i <= 2*n ; ++i)
    {
        nodes[i].val = INF;
        nodes[i].leftPos = -1;
        nodes[i].rightPos = -1;
    }

    long root = Huffman(nodes, n);

    DepthFirst(nodes, root);

    long long unsigned lg = 0;
    for (long i = 0; i < n; ++i)
    {
        lg += len[i] * nodes[i].val;
    }

    g << lg << '\n';

    for (long i = 0; i < n; ++i)
    {
        g << len[i] << ' ' << code[i] << '\n';
    }

    f.close();
    g.close();

    return 0;
}