#include <iostream>
using namespace std;
int main(){
  int n;
  cin>>n;
  int x,y;
  x=0;
  y=0;
  for(int i=2015; i<=n; ++i){
    int d;
    d=365;
    if(i%4==0){
      if(i%100==0){
        if(i%400==0){
          d=366;
        }
      } else {
        d=366;
      }
    }
    x+=d%7;
    if(x==0) y++;
    else if(x%7==0) y++;
  }
  cout<<y<<endl;
  return 0;
}