#include<cstdio>
const int N=1000001,M=15000000;
long long q[N];
int n,i,j,k,s[N],d[N],r[N],p[N],e=-1,l;
char u[M];
inline int B()
{
  	int s=0;
  	for(e++;u[e]>='0'&&u[e]<='9';e++)
  		s=s*10+u[e]-'0';
  	return s;
}
inline void S(long long x,char c)
{
    int i,j,e[20];
    if(!x)
        u[l++]=48;
    for(j=0;x;x/=10)
        e[j++]=x%10;
    for(i=0;i<j;i++)
        u[l+j-i-1]=e[i]+48;
    u[l+j]=c,l+=j+1;
}
inline void A(int k,long long a,int b)
{
    if(k>n)
		A(s[k-n],2*a,b+1),A(d[k-n],2*a+1,b+1);
	else
		p[k]=b,q[k]=a;
}
int main()
{
    freopen("huffman.in","r",stdin),freopen("huffman.out","w",stdout),fread(u,1,M,stdin),n=B();
    for(i=1;i<=n;i++)
        q[i]=N,r[i]=B();
    for(k=j=i=1;i<n;q[0]+=q[i++])
    	if(k<n&&r[k+1]<=q[j])
        	q[i]=r[k]+r[k+1],s[i]=k++,d[i]=k++;
    	else if(q[j+1]<=r[k]||k==n+1)
        	q[i]=q[j]+q[j+1],s[i]=n+j++,d[i]=n+j++;
    	else
        	q[i]=r[k]+q[j],s[i]=k++,d[i]=n+j++;
    S(q[0],'\n'),A(2*n-1,0,0);
    for(i=1;i<=n;i++)
        S(p[i],' '),S(q[i],'\n');
    fwrite(u,1,l,stdout);
}