#!usr/bin/env ruby
# -*- coding: utf-8 -*-

def search(target_num,input)
  input.each_with_index do |num,index|
    if num == target_num
      puts "#{index +1}番目"
      return
    end
  end
  puts "ないよ"
end

input = [6,1,2,5,7,9,25,4]
search(1,input)