#include <stdio.h>
#include <queue>

#define int64 long long int
#define arb node*

using namespace std;

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

class myComp
{
  public:
  bool operator() (const arb lhs, const arb rhs) const
  {
    return (lhs->frecv > rhs->frecv);
  }
};

priority_queue<arb, vector<arb>, myComp> A;
queue<arb> Init;
int n;
int64 S;
int V_h[1000001];
int64 V_val[1000001];

void read_() {
     scanf("%d", &n);
     for (int i = 0; i < n; i++) {
         arb El = new node();
         scanf("%lld", &(El->frecv));
         El->poz = i;
         Init.push(El);
     } 
     arb El = new node();
     El->frecv = 100000001;
     Init.push(El);
     
     node *El1, *El2, *Fin;
     for (int i = 1; i < n; i++) {
         if (A.size() == 0 || (A.top())->frecv > (Init.front())->frecv) {
             El1 = Init.front();
             Init.pop();       
         }
         else  {
             El1 = A.top();
             A.pop();    
         } 
         
         if (A.size() == 0 || (A.top())->frecv > (Init.front())->frecv) {
             El2 = Init.front();
             Init.pop();       
         }
         else  {
             El2 = A.top();
             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_() {     
    printf("%lld\n", S);
    for (int i = 0; i < n; i++) {
        printf("%d %lld\n", V_h[i], V_val[i]);
    }     
}

int main() {
    freopen("huffman.in", "r", stdin);
    freopen("huffman.out", "w", stdout);
    
    read_();        
    dfs_(A.top(), 0, 0);    
    print_();
    
    return 0;
}