#include <iostream>
using namespace std;
typedef long long ll;

ll calc(ll a){
  ll x=0;
  if(a%4==0){
    x=1;
    if(a%100==0){
      x=0;
      if(a%400==0){
        x=1;
      }
    }
  }
  return x;
}

int main(){
  ll N;
  cin>>N;
  ll x=0,y=0;
  for(ll i=2015; i<=N; ++i){
    x+=1;
    if(calc(i)) x+=1;
    if(x==7) x=0, y+=1;
    if(x==8) x=1;
  }
  cout<<y<<endl;
  return 0;
}