#include <iostream>
#include <fstream>
#include <algorithm>
#include <math.h>
#define MAX_HEAP_SIZE 1000001

using namespace std;
ifstream in;
ofstream out;
class nod{
public:
    unsigned long long int lu;
    unsigned long long int st;
    unsigned long long int dr;
};
nod coada1[2*MAX_HEAP_SIZE];
unsigned long long int n, pos[MAX_HEAP_SIZE], nr, c=1, T, NUMAR_AIUREA, lg[MAX_HEAP_SIZE], b[MAX_HEAP_SIZE];
char cod [64];int contor, contor2;

int defeu (int k)
{
    NUMAR_AIUREA=0;
    if(coada1[k].st && coada1[k].dr)
    {
        {
            cod[contor]=0;
            ++contor;
            defeu(coada1[k].st);

        }
        {
            cod[contor]=1;
            ++contor;
            defeu(coada1[k].dr);

        }
    }
    else
    {
    lg[k]=contor;
    for(int j=0;j<contor;++j)
        NUMAR_AIUREA+=pow(2, contor-1-j) * cod[j];
    b[k]=NUMAR_AIUREA;
    }
    --contor;


}
///PANA AICI AU FOST PORCARIILE ALEA DE LA HEAP
int main()
{
    int st1=1, dr1=1, st2=0, dr2=0;
    in.open ("huffman.in");
    out.open ("huffman.out");
    in>>n;
    st2=n+1;dr2=n+1;
    for(int i=1;i<2*n;++i)
        coada1[i].lu=2e16;
    for(dr1 = 1;dr1<=n;++dr1)
    {
        in>>coada1[dr1].lu;
        pos[dr1]=c;
        ++c;
    }
    ///amu algoritmu propriu-zis
    nod r, k;
    int s, j;
    for(int i=n+1;i<2*n;++i)
    {
        ///luam doua cele mai scurte siruri
        if(coada1[st1].lu<coada1[st2].lu && st1 <=n)
        {
            r=coada1[st1];
            s=pos[st1];
            ++st1;
        }
        else
        {
            r=coada1[st2];
            s=pos[st2];
            ++st2;
        }
        if(coada1[st1].lu<coada1[st2].lu && st1 <=n)
        {
            k=coada1[st1];
            j=pos[st1];
            ++st1;
        }
        else
        {
            k=coada1[st2];
            j=pos[st2];
            ++st2;
        }
        coada1[dr2].st=s;
        coada1[dr2].dr=j;
        coada1[dr2].lu=r.lu+k.lu;
        pos[dr2]=c;
        ++dr2;
        ++c;
    }
    for(int i=n+1;i<2*n;++i)
        T+=coada1[i].lu;
    /*for(int i=1;i<2*n;++i)
        cout<<pos[i]<<" ";
        cout<<endl;
    for(int i =1;i<2*n;++i)
        cout<<coada1[i].st<<" "<<coada1[i].lu<<" "<<coada1[i].dr<<"\n";*/
    out<<T<<"\n";
    defeu(2*n-1);
    for(int i=1;i<=n;++i)
        out<<lg[i]<<" "<<b[i]<<"\n";
    in.close();
    out.close();
    return 0;
}