#include <fstream>
#include <queue>

struct Node
{
    long long freq;
    int l, r;
    Node() : freq(), l(-1), r(-1) {}
    Node(long long a) : freq(a), l(-1), r(-1) {}
    Node(long long a, int b, int c) : freq(a), l(b), r(c) {}
};

struct Pair
{
    long long a, b;
    Pair() : a(), b() {}
    Pair(long long c, long long d) : a(c), b(d) {}
};

int extract(std::queue<int> &A, std::queue<int> &B, std::vector<Node> &myV);
void dfs(int nod, std::vector<Node> &myV, Pair *myP, long long &sum, long long s, long long d);

int main()
{
    std::ifstream in("huffman.in");
    std::ofstream out("huffman.out");
    int nV;
    long long nr;
    in >> nV;
    std::vector<Node> myV;
    std::queue<int> myQ1, myQ2;
    for(int i = 0; i < nV; i++)
        in >> nr, myQ1.push(i), myV.push_back(Node(nr));

    Pair *myP = new Pair[nV];
    int a, b;

    while(true)
    {
        a = extract(myQ1, myQ2, myV);
        b = extract(myQ1, myQ2, myV);
        if(b == -1)
            break;
        else
        {
            myV.push_back(Node(myV[a].freq + myV[b].freq, a, b));
            myQ2.push(myV.size() - 1);
        }
    }

    nr = 0;

    dfs(a, myV, myP, nr, 0, 0);

    out << nr << '\n';

    for(int i = 0; i < nV; i++)
        out << myP[i].a << ' ' << myP[i].b << '\n';
    return 0;
}

void dfs(int nod, std::vector<Node> &myV, Pair *myP, long long &sum, long long s, long long d)
{
    if(myV[nod].l == myV[nod].r)
    {
        myP[nod].a = s;
        myP[nod].b = d;
    }
    else
    {
        sum += myV[nod].freq;
        dfs(myV[nod].l, myV, myP, sum, s + 1, d * 2);
        dfs(myV[nod].r, myV, myP, sum, s + 1, d * 2 + 1);
    }
}

int extract(std::queue<int> &A, std::queue<int> &B, std::vector<Node> &myV)
{
    int a = 0;
    if(A.empty() && B.empty())
        return -1;
    else if(A.empty())
    {
        a = B.front();
        B.pop();
        return a;
    }
    else if(B.empty())
    {
        a = A.front();
        A.pop();
        return a;
    }
    else if(myV[A.front()].freq < myV[B.front()].freq)
    {
        a = A.front();
        A.pop();
        return a;
    }
    else
    {
        a = B.front();
        B.pop();
        return a;
    }
}