#include <stdio.h>
#include <queue>
#include <limits>
#include <fstream>
#include <cstdio>

#define int64 long long int
#define arb node*

using namespace std;

typedef struct node {
    int64 frecv;
    arb left;
    arb right; 
    int poz;       
} node;

queue<arb> A;
queue<arb> Init;
int n;
int64 S;
int V_h[1000001];
int64 V_val[1000001];
ifstream in("huffman.in");
ofstream out("huffman.out", ios::binary);
char buff[12];
char rez[20000001];
char* rezP = rez;
     
int get_nr() {
     in.getline(buff, 12, '\n');
     int tmp = 0;
     for (int i = 0; buff[i] != '\0'; i++) {
         tmp = tmp * 10 + (buff[i] - '0');
     } 
     return tmp;     
}

void read_() {
          
     n = get_nr();
     for (int i = 0; i < n; i++) {
         arb El = new node();
         int x;
         x = get_nr();
         El->frecv = x;        
         El->poz = i;
         Init.push(El);
     } 
     in.close();
}

void solve_() {
     arb El = new node();
     El->frecv = numeric_limits<int64>::max();
     Init.push(El);
     
     node *El1, *El2, *Fin;
     for (int i = 1; i < n; i++) { 
         if (A.size() == 0 || (A.front())->frecv > (Init.front())->frecv) {
             El1 = Init.front();
             Init.pop();       
         }
         else  {
             El1 = A.front();
             A.pop();    
         } 
         
         if (A.size() == 0 || (A.front())->frecv > (Init.front())->frecv) {
             El2 = Init.front();
             Init.pop();       
         }
         else  {
             El2 = A.front();
             A.pop();    
         } 
         
         Fin = new node();
         Fin->frecv = El1->frecv + El2->frecv;
         Fin->left = El1;
         Fin->right = El2; 
         
         A.push(Fin);  
         S += Fin->frecv; 
         //printf("%lld %lld -> %lld\n", El1->frecv, El2->frecv, Fin->frecv);  
     }
}

void dfs_(arb H, int h, int64 val) {         
     if (H->left != NULL) {
         dfs_(H->left, h + 1, val << 1);
     }
     if (H->right != NULL) {
         dfs_(H->right, h + 1, (val << 1) + 1);
     }   
     if (H->left == NULL && H->right == NULL) { 
         V_h[H->poz] = h;
         V_val[H->poz] = val;      
     }
}


void print_2() {    
    //char rez[20000001];
    printf("%lld\n", S);
    for (int i = 0; i < n; i++) {
        printf("%d %lld\n", V_h[i], V_val[i]);
    }
}

void print_nr(int64 nr, bool newL){
    if (nr == 0) {
        rezP[0] = '0';
        if (newL) {
            rezP[1] = '\n';        
        } else {
            rezP[1] = ' ';       
        }
        rezP += 2;
    }  
    else {
        int crt = 0;
        char cuv[20];
        while (nr != 0) {
             cuv[crt++] = nr % 10;
             nr /= 10;     
        } 
        for (int i = crt - 1; i >= 0; i--) {
             rezP[crt - 1 - i] = cuv[i] + '0';
        }   
         if (newL) {
            rezP[crt] = '\n';        
        } else {
            rezP[crt] = ' ';       
        } 
        rezP += (crt + 1); 
    }
}

void print_() {
    print_nr(S, true);
    for (int i = 0; i < n; i++) {
        print_nr(V_h[i], false);
        print_nr(V_val[i], true);
    }    
    out.write(rez,rezP - rez);  
}
 
   
int main() {
    //freopen("huffman.in", "r", stdin);
    freopen("huffman.out", "w", stdout);
    
    read_();  
    solve_();
    dfs_(A.front(), 0, 0);
    print_();
    
    in.close();
    return 0;
}