Problem Link:

CHDIGER

Description

Chef Leonardo has a decimal integer N and a non-zero decimal digit d. N does not contain the digit zero; specifically, N should always be treated as a decimal integer without leading zeroes.

Chef likes d and does not like any other digit, so he decided to change N. He may apply the following operation any number of times (including zero): append the digit d to the decimal representation of N (d becomes the least significant digit of N), then remove one occurrence of one digit from the decimal representation of N.

Chef has already changed a lot of numbers and he got bored. Now, he wants to know the smallest possible value of N which can be obtained by performing the operation described above. Can you help him?