#!/usr/koeki/bin/ruby

#!/usr/koeki/bin/ruby

def factorial(n)
  if n == 1
    1
  else
    n * factorial(n-1)
  end
end

n = 1
# n = 2
# n = 3

#n = gets.chomp.to_i

printf("%d¤Î³¬¾è¤Ï%d¤Ç¤¹\n", n, factorial(n))