#include <fstream>
#include <cstring>
#define nmax 1000005
using namespace std;
ifstream f("huffman.in");
ofstream g("huffman.out");
pair <long long,pair <int,int> > p[nmax*2];
long long v[nmax],w[nmax],c[nmax],ans;
int n,m,h[nmax];

void dfs(int nod,int cod,int niv)
{
    if (nod<=n) {
        c[nod]=cod;
        h[nod]=niv;
    }
    if (nod>n)
        ans+=p[nod].first;
    if (p[nod].first>0) {
        dfs(p[nod].second.first,cod*2,niv+1);
        dfs(p[nod].second.second,cod*2+1,niv+1);
    }
}
int main()
{
    int i,j,k;
    memset(v,1,sizeof(v));
    memset(w,1,sizeof(w));
    f>>n;
    for (i=1;i<=n;i++)
        f>>v[i];

    i=1,j=1;m=0;
    for (k=n;k<2*n-1;) {
        if (v[i+1]<w[j]) {
            k++;
            p[k]=make_pair(v[i]+v[i+1],make_pair(i,i+1));
            m++;
            w[m]=v[i]+v[i+1];
            i+=2;
            continue;
        }
        if (w[j+1]<v[i]) {
            k++;
            p[k]=make_pair(w[j]+w[j+1],make_pair(n+j,n+j+1));
            m++;
            w[m]=w[j]+w[j+1];
            j+=2;
            continue;
        }
        k++;
        p[k]=make_pair(v[i]+w[j],make_pair(i,n+j));
        m++;
        w[m]=v[i]+w[j];
        i++,j++;
    }
    dfs(2*n-1,0,0);
    g<<ans<<'\n';
    for (i=1;i<=n;i++)
        g<<h[i]<<' '<<c[i]<<'\n';
    return 0;
}