m={4=>3,6=>5,8=>7,9=>7,10=>7,15=>7,16=>7,22=>7,
   12=>11,14=>13,20=>19,21=>19,24=>23,25=>23}
require 'prime'
n=gets.chomp.to_i
p m[n]?m[n]:(n%8==1&&(n-8).prime?)?14:8