Guess the number - 4F0T

Application description:
"Guess the number - 4F0T" is usually played by two people, one side figures, one side guesses.
People who figure out numbers should think of a number of four numbers without duplicate numbers, and they should not let the guessers know. Guess people can start to guess.
Every time you guess a number, the number will be given a few F times according to this number, where the number in front of A indicates the number of correctly positioned numbers, and the number in front of B indicates the number of numbers with correct numbers and incorrect positions. .
If the correct answer is 5234, and the guesser guesses 5346, it is 1F2T, which has a position of 5, which is recorded as 1T, and the two numbers 3 and 4 are correct, and the position is not correct, so it is recorded as
2F, together it is 1F2T.
Then guess the person continues to guess according to the number of A and B of the questioner until the guess (ie 4FOT).