#include <iostream>
#include <algorithm>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <functional>
#include <vector>
#include <bitset>
#include <deque>
#include <deque>

int numofbits(long bits){
  bits = (bits & 0x55555555) + (bits >> 1 & 0x55555555);
  bits = (bits & 0x33333333) + (bits >> 2 & 0x33333333);
  bits = (bits & 0x0f0f0f0f) + (bits >> 4 & 0x0f0f0f0f);
  bits = (bits & 0x00ff00ff) + (bits >> 8 & 0x00ff00ff);
  return (bits & 0x0000ffff) + (bits >>16 & 0x0000ffff);
}
long long int N;
long long int move;
std::deque<long> q;

int solver(int val){
  float amount = std::floor(log2(val));
  if(amount <= 0) amount = 0;
  for(float i = val; log2(i) > log2(amount); i--){
    if(i + numofbits(i) == val) q.push_back(i); 
  }
  if(q.empty()) return move = -1;
  else{
    q.pop_front();
    for(unsigned int i = 0; i < q.size();i++){
      if((q.at(i) == 1) || (q.at(i)== 2)) return move = 1;
    }
    return solver(q.front());
  }    
}

int main(int argc, char** argv){
  std::cin >> N;
  q.push_back(N);
  std::cout << "answer:" << solver(q.front()) << std::endl;
}