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#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>

using namespace std;

vector<int> v[100];

int main() {
  ios_base::sync_with_stdio(false);

  int k;
  cin >> k;
  vector<int> bits;

int sumBits = 0;
  while(k > 0) {
    bits.push_back(k%3);
    sumBits += k%3;
    k /= 3; 
  }
  reverse(bits.begin(), bits.end());

  for(int i = 0; i < sumBits; ++i) {
    v[i].push_back(i+1);
  }

  int total = sumBits+1+(bits.size()-1)*3;
  int bitsv = 0;
  if(bits[0] == 2)
    v[bitsv++].push_back(sumBits);

  for(int i = 0; i < bits.size()-1; ++i) {
    v[sumBits+3*i].push_back(sumBits+3*i+1);
    v[sumBits+3*i].push_back(sumBits+3*i+2);
    v[sumBits+3*i+1].push_back(sumBits+3*i+2);
    v[sumBits+3*i+1].push_back(sumBits+3*i+3);
    v[sumBits+3*i+2].push_back(sumBits+3*i+3);
    if(bits[i+1] >= 1)
    v[bitsv++].push_back(sumBits+3*i+3);
    if(bits[i+1] == 2)
    v[bitsv++].push_back(sumBits+3*i+3);
  }
  
  cout << total << '\n';
  for(int i = 0; i < total; ++i) {
    if(v[i].empty()) { 
      cout << "-1 -1\n";
    }
    else if(v[i].size() == 1) {
      cout << v[i][0]+1 << " -1\n";
    }
    else {
      cout << v[i][0]+1 << ' ' << v[i][1]+1 << '\n';
    }
  }
}