#include <iostream>
#include <fstream>
#define MAX_HEAP_SIZE 1000001

using namespace std;
struct nod{
    unsigned long long int lu;
    unsigned int st;
    unsigned int dr;
};
nod coada1[2*MAX_HEAP_SIZE];
unsigned long long int n, T, lg[MAX_HEAP_SIZE], b[MAX_HEAP_SIZE];
unsigned int pos[2*MAX_HEAP_SIZE], c=1;
const unsigned long long int inf=0x3f3f3f3f3f3f3f3fLL;
void defeu (int k, long long cod, int nivel)
{
    if(coada1[k].st && coada1[k].dr)
    {
            defeu(coada1[k].st, cod*2, nivel+1);
            defeu(coada1[k].dr, cod*2+1, nivel+1);
            return;
    }
    lg[k]=nivel;
    b[k]=cod;
}
int main()
{
    int st1=1, dr1=1, st2=0, dr2=0, i;
    ifstream in ("huffman.in");
    ofstream out ("huffman.out");
    in>>n;
    st2=n+1;dr2=n+1;
    for(i=n;i<2*n;++i)
        coada1[i].lu=inf;
    for(dr1 = 1;dr1<=n;++dr1)
    {
        in>>coada1[dr1].lu;
        pos[dr1]=c;
        ++c;
    }
    ///amu algoritmu propriu-zis
    long long unsigned int r, k, s, j;
    coada1[st2].lu=inf;
    for(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].lu;
            s=pos[st1];
            ++st1;
        }
        else
        {
            r=coada1[st2].lu;
            s=pos[st2];
            ++st2;
        }
        if(coada1[st1].lu<coada1[st2].lu && st1 <=n)
        {
            k=coada1[st1].lu;
            j=pos[st1];
            ++st1;
        }
        else
        {
            k=coada1[st2].lu;
            j=pos[st2];
            ++st2;
        }
        coada1[dr2].st=s;
        coada1[dr2].dr=j;
        coada1[dr2].lu=r+k;
        T+=coada1[dr2].lu;
        pos[dr2]=c;
        ++dr2;
        //if(!coada1[dr2].lu)
        //    coada1[dr2+1].lu=inf;
        ++c;
    }
    /*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, 0, 0);
    for(i=1;i<=n;++i)
        out<<lg[i]<<" "<<b[i]<<"\n";
    in.close();
    out.close();
    return 0;
}