#include <fstream>
#include <queue>
#define nMax 2000050
typedef long long ll;

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

ll fr[nMax], ln[nMax], b10[nMax], G[nMax][5];
queue<int> Q[5];

int Min()
{
    int x;
    if(Q[1].empty())
    {
        x = Q[2].front();
        Q[2].pop();
        return x;
    }
    if(Q[2].empty())
    {
        x = Q[1].front();
        Q[1].pop();
        return x;
    }
    if(fr[Q[1].front()] <= fr[Q[2].front()])
    {
        x = Q[1].front();
        Q[1].pop();
        return x;
    }
    x = Q[2].front();
    Q[2].pop();
    return x;
}

void dfs(int nod, ll val, int len)
{
    if(G[nod][0]==0)
    {
        ln[nod]=len;
        b10[nod]=val;
        return;
    }
    dfs(G[nod][0], val<<1LL, len+1);
    dfs(G[nod][1], (val<<1LL)+1, len+1);
}

int main()
{
    int n;
    fin >> n;
    for(int i=1; i<=n; i++)
    {
        fin >> fr[i];
        Q[1].push(i);
    }
    int nr=n;
    ll lg=0;
    while((Q[1].size()+Q[2].size())!=1)
    {
        int l=Min();
        int r=Min();
        Q[2].push(++nr);
        fr[nr]=fr[l]+fr[r];
        lg+=fr[nr];
        G[nr][0]=l;
        G[nr][1]=r;
    }
    dfs(nr, 0, 0);
    fout << lg << "\n";
    for(int i=1; i<=n; i++)
        fout << ln[i] << " " << b10[i] << "\n";
    return 0;
}