#include <iostream>
using namespace std;

int main()
{
  int n, locate, bitcount, movenum;
  int road[10000], through[10000];
  cin >> n;
  locate=1;
  for( int i=0; i<n; ++i )through[i]=0;
  for( int i=0; i<n; ++i )
  {
    if( n==locate )
    {
      movenum=i;
      i=n;
    }
    else if( 1==locate && 0<through[0] )
    {
      movenum=-1;
      i=n;
    }
    else
    {
      road[i]=locate;
      through[locate-1]=1;
      for(int j=locate; j>1; j>>=1)through[locate-1]+=j&1;
      if(n<locate+through[locate-1] || 0<through[locate-1+through[locate-1]])
      {
        if(0>=locate-through[locate-1] || 0<through[locate-1-through[locate-1]])
        {
          locate=road[i-1];
          i--;
        }
        else locate-=through[locate-1];
      }
      else locate+=through[locate-1];
    }
  }
  cout << movenum << endl;
  return 0;
}