//
//  main.cpp
//  coduri hoofman
//
//  Created by Eusebiu Rares on 29/05/2020.
//  Copyright © 2020 Eusebiu Rares. All rights reserved.
//

#include <iostream>
#include "fstream"
#include "queue"

#define level left
#define cod right

#define left first
#define right second

const int MV = 2e6 ;

std::fstream in ("huffman.in", std::ios::in) ;
std::fstream out ("huffman.out", std::ios::out) ;

long long id[MV + 1] ;
std::queue<int> firstQueue, secondQueue ;
int nodes ;
std::pair <int, int> arb[MV + 1] ;
int code[MV + 1] ;
long long code2[MV + 1] ;

int small() {
	if (firstQueue.empty()) {
		int candidateA = secondQueue.front() ;
		secondQueue.pop() ;
		return candidateA ;
	}
	if (secondQueue.empty()) {
		int candidateA = firstQueue.front() ;
		firstQueue.pop() ;
		return candidateA ;
	}
	int candidateA = firstQueue.front() ;
	int candidateB = secondQueue.front() ;
	if (id[candidateA] <= id[candidateB]) {
		firstQueue.pop() ;
		return candidateA ;
	} else {
		secondQueue.pop() ;
		return candidateB ;
	}
}

void addNode(int x, int y) {
	id[++ nodes] = id[x] + id[y] ;
	secondQueue.push(nodes) ;
	arb[nodes] = {x, y} ;
}

void createArb() {
	while (firstQueue.size() + secondQueue.size() >= 2) {
		int smallest = small() ;
		int help = small() ;
		addNode(smallest, help) ;
	}
}

void dfs(int node) {
	code[arb[node].left] = code[node] + 1 ;
	code[arb[node].right] = code[node] + 1 ;
	code2[arb[node].left] = code2[node] << 1 ;
	code2[arb[node].right] = (code2[node] << 1) + 1 ;
	if (arb[node].left != 0)
		dfs(arb[node].left) ;
	if (arb[node].right != 0)
		dfs(arb[node].right) ;
}

int main(int argc, const char * argv[]) {
	int codes ; in >> codes ;
	for (int i = 1 ; i <= codes ; ++ i) {
		in >> id[i] ;
		firstQueue.push(i) ;
	}
	nodes = codes ;
	createArb() ;
	dfs(nodes) ;
	long long lg(0) ;
	for (int i = nodes ; i > codes ; -- i) {
		lg += id[i] ;
	}
	out << lg << '\n' ;
	for (int i = 1 ; i <= codes ; ++ i) {
		out << code[i] << ' ' << code2[i] << '\n' ;
	}
}