require 'prime'
require 'date'

n = gets.to_i+1
a = [0]
(Date.parse("19700101")..Date.parse("20191231")).each{|i|
  a[-1]+=1;a << 0 if i.to_s.gsub(?-,"").to_i.prime?
}
m = t = a[0...n].inject(:+)
(a.size-n).times{|i|
  m=[t+=a[i+n]-a[i],m].max
}
p m-1