#!/usr/koeki/bin/ruby

honsu = 0
ninzu = 0

while rental_data = gets
  if /(\S+)\s+(\S+)\s+(\d+)/ =~ rental_data
#    print rental_data
    ninzu += 1
    honsu += $3.to_f
  end
end

printf("本日の客単価は %4.1f [レンタル本数/人] でした\n", honsu / ninzu * 100)