I need to find a function that takes two integers as input and outputs an integer.
Input : $28$ $1$
Output : $68$
Input : $39$ $1$
Output : $90$
Input : $90$ $1$
Output : $81$
Input : $15$ $2$
Output : $40$
Input : $123$ $2$
Output : $17$
Input : $114514$ $1919$
Output : $16$