package _0087;

import java.time.DayOfWeek;
import java.time.LocalDate;
import java.util.Scanner;
import java.util.stream.IntStream;

public class Main {

    public static void main(String[] args) {
        Scanner stdin = new Scanner(System.in);
        int n = stdin.nextInt();
        
        int month = 7;
        int day = 23;
        DayOfWeek first = LocalDate.of(2014, month, day).getDayOfWeek();
        
        long ans = IntStream.rangeClosed(2015, n)
                            .mapToObj(year -> LocalDate.of(year, month, day).getDayOfWeek())
                            .filter(dayOfWeek -> dayOfWeek == first)
                            .count();
        System.out.println(ans);
    }

}