#include <cstdio>
#include <queue>
  
using namespace std;
  
struct node {
    
  node (long long val, int leaf) {
    for (auto &x : next_node) {
      x = NULL;
    }
    this -> val = val;
    this -> leaf_cnt = leaf;
  }
  
  int leaf_cnt;
  long long val;
  node* next_node[2];
};
  
void get_cur(queue < node* > &in_q, queue < node* > &sec_q, node* &cur_n) {
  
  if (in_q.size() and sec_q.size()) {
    if (in_q.front() -> val <= sec_q.front() -> val) {
      cur_n = in_q.front();
      in_q.pop();
    }
    else {
      cur_n = sec_q.front();
      sec_q.pop();
    }
  }
  else if (in_q.size()) {
    cur_n = in_q.front();
    in_q.pop();
  }
  else {
    cur_n = sec_q.front();
    sec_q.pop();
  }  
}
 
void Dfs(long long bin, int len, node* cur_node,
  vector < pair < int, long long > > &ans) {
  
  if (cur_node -> leaf_cnt) {
    ans[cur_node -> leaf_cnt] = {len, bin};
    return;
  }
  
  Dfs(bin << 1, len + 1, cur_node -> next_node[0], ans);
  Dfs(bin << 1 | 1, len + 1, cur_node -> next_node[1], ans);
}
  
int main(int argc, char const *argv[]) {
    
  freopen("huffman.in", "r", stdin);
  freopen("huffman.out", "w", stdout);
 
  int n;  
  scanf("%d", &n);
  
  node* cur = NULL;
  node* cur_left = NULL;
  node* cur_right = NULL;
  queue < node* > in_q;
  queue < node* > sec_q;
  vector < pair < int, long long > > ans(n + 1);

  for (int i = 1; i <= n; i ++) {
      
    int val;
    scanf("%d\n", &val);
    in_q.push(new node(1ll * val, i));
  }
  
  long long sum = 0;
  while (in_q.size() + sec_q.size() > 1) {
  
    get_cur(in_q, sec_q, cur_left);
    get_cur(in_q, sec_q, cur_right);
  
    cur = new node(cur_left -> val + cur_right -> val, false);
    cur -> next_node[0] = cur_left;
    cur -> next_node[1] = cur_right;
    sec_q.push(cur);
    sum += cur -> val;
  }
  
  printf("%lld\n", sum);
  Dfs(0, 0ll, cur, ans);
  for (int i = 1; i <= n; i ++) {
    printf("%d %lld\n", ans[i].first, ans[i].second);
  }
}