/*
TASK:necklace
LANG:C++
*/
#include <iostream>
#include <fstream>
using namespace std;
int rec(int);
int rec(int p,int q)
{ 
  int d=abs(p-q);
  int br=0;
  if (p<=1) return br;
  if (d%3==0) br=br+1;
  rec(p-1,q-1);
}
int main()
{
    int n,x,y,end;
    cin >> n;
    if (n%2==0) {x=n/2;y=n/2;}
    else x=(n%2)+1;y=n/2;
    end=rec(x,y);
    if ((n==1)||(n==2)||(n==3))
    {cout << 0;}
    cout << 9;
return 0;
}

