#!/usr/bin/env ruby

require 'trollop'


STDIN.set_encoding 'utf-8'
STDOUT.set_encoding 'utf-8'

def usage
  STDERR.write "./sample --size <n> < <line separated data>\n"
  exit 1
end
usage if ARGV.size!=4

opts = Trollop::options do
  opt :size, "Sample n% (percentage).", :type => :int
end


prng = Random.new(Random.new_seed)

while line = STDIN.gets
  STDOUT.write line if prng.rand(1..opts[:size])==0
end