#include<fstream.h>
#define N 2000001
typedef struct nod
{long info,val;
nod *st,*dr;}Nod;
long long q2[N];
long n,i,j,k;
unsigned int q1[N];
Nod *p[N],*l;

Nod *make(long x,long y,Nod *left,Nod *right)
{Nod *r=new Nod;
r->info=x;
r->val=y;
r->st=left;
r->dr=right;
return r;}

int main()
{ifstream f1("huffman.in");
ofstream f2("huffman.out");
f1>>n;
for(i=1;i<=n;i++)
       {f1>>q1[i];
       q2[i]=N;
       p[i]=make(q1[i],i,NULL,NULL);}
j=k=1,q2[0]=0;
for(i=1;i<n;i++)
if(k<=n)
        {if(q1[k+1]<=q2[j]&&k+1<=n)
                 {q2[i]=q1[k]+q1[k+1];
                 p[i+n]=make(q2[i],i+n,p[k],p[k+1]);
                 k+=2;}
        else
                 if(q2[j+1]<=q1[k])
                           {q2[i]=q2[j]+q2[j+1];
                           p[i+n]=make(q2[i],i+n,p[j+n],p[j+1+n]);
                           j+=2;}
                 else
                           if(q2[j]<=q1[k]&&q1[k]<=q2[j+1])
                                    {q2[i]=q1[k]+q2[j];
                                    p[i+n]=make(q2[i],i+n,p[j+n],p[k]);
                                    j++;
                                    k++;}
                           else
                                    if(q1[k]<=q2[j]&&((q2[j]<=q1[k+1]&&k+1<=n)||k+1>n))
                                             {q2[i]=q1[k]+q2[j];
                                             p[i+n]=make(q2[i],i+n,p[k],p[j+n]);
                                             j++;
                                             k++;}
        q2[0]+=q2[i];}
else
        {q2[i]=q2[j]+q2[j+1];
        q2[0]+=q2[i];
        p[i+n]=make(q2[i],i+n,p[j+n],p[j+1+n]);
        j+=2;}
f2<<q2[0]<<"\n";
l=p[2*n-1];
k=j=0;
p[j++]=l;
q2[l->val]=q1[l->val]=0;
while(k<j)
        {l=p[k++];
        if(l->st)
                 {q1[l->st->val]=q1[l->val]+1;
                 q2[l->st->val]=q2[l->val]<<1;
                 p[j++]=l->st;}
        if(l->dr)
                 {q1[l->dr->val]=q1[l->val]+1;
                 q2[l->dr->val]=(q2[l->val]<<1)+1;
                 p[j++]=l->dr;}}
for(i=1;i<=n;i++)
        f2<<q1[i]<<" "<<q2[i]<<"\n";
f1.close();
f2.close();
return 0;}