#include <cstdio>
#include <cstdlib>
#include <vector>
#include <string>
#include <queue>
#include <iostream>

using namespace std;

typedef struct treeNode {
	struct treeNode *left;
	struct treeNode *right;
	int weight;
}NOD;  

long long sum;

vector <int> x1, x2;  
queue <NOD*> v1;
queue <NOD*> v2;  

int getmin(queue <NOD*> v1, queue <NOD*> v2) 
{
	int x, y;
	if (v1.size() == 0)
		return 1;
	if (v2.size() == 0)
		return 0;
	x = v1.front()->weight;
	y = v2.front()->weight;
	if (x > y)                                 
		return 1;
	return 0;
} 

int parb(NOD *root, int x, int h)
{
	if (root == NULL)
		return 1;
	if (root->left == NULL && root->right == NULL) {
		sum += (h * root->weight);
		x1.push_back(h);
		x2.push_back(x);
	}
	x = x << 1;
	parb(root->left, x, h+1);
	parb(root->right, x + 1, h+1);
	return 1;
}

int main()
{
	FILE *f = fopen("huffman.in", "rt");
	FILE *g = fopen("huffman.out", "wt");
	int n, i, aux;
	fscanf(f, "%d" , &n);
        
	for (i = 0; i < n; i++) {
		NOD *Node = (NOD *)malloc(sizeof(NOD));
		fscanf(f, "%d" , &aux);
		Node->weight = aux;
		Node->left = NULL;
		Node->right = NULL;
		v1.push(Node);
	}
	while (v1.size() + v2.size() > 1) {
		NOD *Node = (NOD *)malloc(sizeof(NOD));
		Node->weight = 0;
		if (getmin(v1, v2)) {
			if (!v2.empty()) {
				Node->weight += v2.front()->weight;
				Node->left = v2.front();
				v2.pop();
			}
		}
		else {
 			if (!v1.empty()) {
				Node->weight += v1.front()->weight;
				Node->left = v1.front();
				v1.pop();
			}
		}
 		if (getmin(v1, v2)) {
 			if (!v2.empty()) {
				Node->weight += v2.front()->weight;
				Node->right = v2.front();
				v2.pop();
			}
		}
		else {
			if (!v1.empty()) {
				Node->weight += v1.front()->weight;
				Node->right = v1.front();
				v1.pop();
			}
		}
		if (Node->weight != 0) {
			v2.push(Node);
		}	
	}
	parb(v2.front(), 0, 0);
	fprintf(g, "%lld\n", sum);
	for (vector <int>::iterator it = x1.begin(), it2 = x2.begin(); it != x1.end() && it2 != x2.end(); it++, it2++)
		fprintf(g, "%d %d\n", *it, *it2);
	fclose(f);
	fclose(g);
	return 0;
}