import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Scanner;
import java.util.Set;
import java.util.TreeSet;

public class Main {
	
	public static final int zeller(int y, int m, int d){
		if(m <= 2){ y--; m+=12;}
		
		return (d + 26*(m+1)/10 + y + y/4 + 6*(y/100) + y/400) % 7;
	}
	
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		
		final int mod_2014 = zeller(2014, 7, 23);
		
		final int N = sc.nextInt();
		
		int answer = 0;
		for(int i = 2015; i <= N; i++){
			if(zeller(i, 7, 23) == mod_2014){
				answer++;
			}
		}
		
		System.out.println(answer);
	}
	
}