def zeller(_y,m,d)
	m+=1
	if m<4 then _y-=1;m+=12 end
	y=_y/100;z=_y%100
	(5*y+z+y/4+z/4+13*m/5+d-1)%7
end
p (2015..gets.to_i).count{|i|zeller(i,7,23)==zeller(2014,7,23)}