Быки и Коровы

Think it's hard? Thanks to the prompts you can guess in a few tries.

The rules of the game are as follows: the computer plans four different numbers from 1.2, ... 9. The player makes moves to find out these numbers and their order. Each turn consists of four digits. In response, the computer shows the number of guessed figures standing in their places (the number of bulls) and the number of guessed figures standing not in their places (the number of cows). Scroll through the numbers and select a combination. In the selected combination can not be two identical numbers