#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;        
} 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;
int n;
int64 S;

void read_() {
     scanf("%d", &n);
     for (int i = 0; i < n; i++) {
         arb El = new node();
         scanf("%lld", &(El->frecv));
         A.push(El);
     } 
     
     int Size = A.size();
     while (Size > 1) {
         arb El1 = A.top();
         A.pop();
         arb El2 = A.top();
         A.pop();
         
         arb 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);  
         Size--;
     }
}

void write_(arb H, int h, int64 val) { 
     if (H->left == NULL && H->right == NULL) { 
         printf("%d %lld\n", h, val);       
     }
     
     if (H->left != NULL) {
         write_(H->left, h + 1, val << 1);
     }
     if (H->right != NULL) {
         write_(H->right, h + 1, (val << 1) + 1);
     }   
}

int main() {
    freopen("huffman.in", "r", stdin);
    freopen("huffman.out", "w", stdout);
    
    read_();
        
    printf("%lld\n", S);
    write_(A.top(), 0, 0);
    
    return 0;
}