just some test code

sir.rb

sir = gets
array = sir.split
hash = {}
for i in array do
	hash[i] = 0
end

for i in array do
	hash[i]+=1
end

hash.each do|numar,nr_aparitii|
  if nr_aparitii == 2
  	puts "numarul care apare de 2 ori este #{numar}"
  end
end