Muh-Muh
Muh-Muh (also known as Cows and Bulls or Pigs and Bulls) is a complex mind game, predating the similar commercially-marketed board game Master Mind.
Computer named Jenya selects a four digit number, all four digits are different.
Your Job:
find out the 4 numbers Jenya have in mind.
Example:
* Secret number: 4271
* Opponents try: 1234
* Answer: 1 bull and 2 cows. (The bull is "2", the cows are "4" and "1".)