#include <fstream>
#include <queue>

#define maxn 1000100

struct Node
{
    long long freq;
    int l, r;
};

long long myP[maxn][2];
Node myV[2 * maxn];
std::queue<int> A, B;

int extract();
void dfs(int nod, long long &sum, int s, long long d);

int main()
{
    std::ifstream in("huffman.in");
    std::ofstream out("huffman.out");
    int nV;
    long long nr;
    in >> nV;
    for(int i = 0; i < nV; i++)
        in >> nr, A.push(i), myV[i].freq = nr, myV[i].l = -1, myV[i].r = -1;

    int c = nV;

    int a, b;

    while(true)
    {
        a = extract();
        b = extract();
        if(b == -1)
            break;
        else
        {
            myV[c].freq = myV[a].freq + myV[b].freq;
            myV[c].l = a;
            myV[c].r = b;
            B.push(c);
            c++;
        }
    }

    nr = 0;

    dfs(a, nr, 0, 0);

    out << nr << '\n';

    for(int i = 0; i < nV; i++)
        out << myP[i][0] << ' ' << myP[i][1] << '\n';
    return 0;
}

void dfs(int nod, long long &sum, int s, long long d)
{
    if(myV[nod].l == myV[nod].r)
    {
        myP[nod][0] = s;
        myP[nod][1] = d;
    }
    else
    {
        sum += myV[nod].freq;
        dfs(myV[nod].l, sum, s + 1, d << 1);
        dfs(myV[nod].r, sum, s + 1, (d << 1) + 1);
    }
}

int extract()
{
    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;
    }
}