#include <iostream>
using namespace std;

int main()
{
  int n, lane, bit, mov;
  int through[10050];
  bool check[10000];
  bool flg, hit;
  cin >> n;
  flg=true; hit=false;
  through[0]=1; check[0]=true;
  for( int i=1; i<n; ++i ){ through[i]=0; check[i]=true; }
  while( flg )
  {
    for( int i=0; i<n; ++i )
    {
      if( 0<through[i] && check[i] )
      {
        bit=1;
        for( int j=i+1; 1<j; j>>=1 )bit+=j&1;
        lane=(i-bit)*(0==i);
        mov=through[i]+1*(0==i);
        check[i]=false;
        through[lane]*=(through[lane]<=mov);
        flg=(0==through[lane]);
        while( n-1>lane && 0==through[lane] )
        {
          through[lane]=mov;
          bit=1;
          for( int j=lane+1; 1<j; j>>=1 )bit+=j&1;
          lane+=bit;
          mov++;
          through[lane]*=(through[lane]<=mov);
        }
        if(n-1==lane)
        {
          hit=true;
          through[n-1]=mov;
        }
      }
    }
    if(hit)flg=false;
  }
  if(!hit)mov=-1;
  cout << mov << endl;
  return 0;
}