#include<iostream>
#include<fstream>
#include<vector>
#include<queue>
#include<string.h>
#include<math.h>
#include<map>

using namespace std;

ofstream out("huffman.out");

struct Node{
	long long value;
	string cod;
	Node *right;
	Node *left;
};

typedef struct Node *tNode;

struct cmp{
	bool operator() (tNode const &p1, tNode const &p2){
		return p1->value > p2->value;
	}
};


tNode createNode(long long val, tNode left, tNode right){
	tNode node=new Node();
	node->value=val;
	node->right=right;
	node->left=left;
	node->cod="";
	return node;
}


tNode buildTree(){
	ifstream in("huffman.in");
	priority_queue<tNode,vector<tNode>,cmp> forest;
	int n,i;
	tNode node1, node2;
	long long x,lg=0; 
	in>>n;
	
	for(i=1;i<=n;i++) {
		in>>x;
		tNode node=createNode(x,NULL,NULL);
		forest.push(node);
	}
	in.close();
	
	while(forest.size()>1){
	   node1=forest.top();
	   forest.pop();
	   node2=forest.top();
	   forest.pop();
	   lg+=node1->value+node2->value;
	   forest.push( createNode(node1->value+node2->value,node1,node2) ); 	
	}
	out<<lg<<'\n';
	return forest.top(); 
}


long long dec(string s){
	long long sol=0, p=pow(2,s.size());
	for(int i=0;i<s.size();i++){
		p=p/2;
		if(s[i]=='1')  sol=sol+p;
	}
	return sol;
}


vector< pair<int,int> > readTree(tNode node, string s){
	  
	  vector< pair<int,int> > sol;
	  queue<tNode>q;
	  q.push(node);
	  
	  while(!q.empty()){
	  	tNode node=q.front();
	  	q.pop();
	  	if(node->right==NULL && node->left==NULL) 
		  sol.push_back(make_pair(node->cod.size(),dec(node->cod)));
	  	if(node->right!=NULL){
	  		node->right->cod=node->cod+"1";
		    q.push(node->right);
		  } 
	  	if(node->left!=NULL){
	  		node->left->cod=node->cod+"0";
		    q.push(node->left);
		  } 
	  }
	  
	  return sol;
}


int main(){
	vector< pair<int,int> > sol=readTree(buildTree(),"");
	for(int i=sol.size()-1;i>=0;i--) 
	    out<<sol[i].first<<" "<<sol[i].second<<'\n';
    return 0;
}