#include<cstdio>
#define N 2000000
long long q[N];
int n,i,j,k,r[N],s[N],d[N],p[N];
int main()
{freopen("huffman.in","r",stdin);
freopen("huffman.out","w",stdout);
scanf("%d",&n);
for(j=k=i=1;i<=n;i++)
       scanf("%d",&r[i]),q[i]=N;
for(i=1;i<n;i++)
if(k<=n)
       if(r[k+1]<=q[j]&&k<n)
                r[i+n]=q[i]=r[k]+r[k+1],s[i+n]=k,d[i+n]=k+1,k+=2,q[0]+=q[i];
       else
                if(q[j+1]<=r[k])
                          r[i+n]=q[i]=q[j]+q[j+1],s[i+n]=j+n,d[i+n]=j+1+n,j+=2,q[0]+=q[i];
                else
                          if(q[j]<=r[k]&&r[k]<=q[j+1])
                                    r[i+n]=q[i]=r[k]+q[j],s[i+n]=j+n,d[i+n]=k,j++,k++,q[0]+=q[i];
                          else
                                    r[i+n]=q[i]=r[k]+q[j],s[i+n]=k,d[i+n]=j+n,j++,k++,q[0]+=q[i];
else
       r[i+n]=q[i]=q[j]+q[j+1],s[i+n]=j+n,d[i+n]=j+1+n,j+=2,q[0]+=q[i];
printf("%lld\n",q[0]),k=j=0,r[j++]=2*n-1;
for(i=r[k];k<j;i=r[k++])
if(s[r[k]])
        p[s[i]]=p[d[i]]=p[i]+1,q[s[i]]=q[i]<<1,q[d[i]]=q[s[i]]+1,r[j++]=s[i],r[j++]=d[i];
for(i=1;i<=n;i++)
        printf("%d %lld\n",p[i],q[i]);
return 0;}