Excel Fill Single Values in a Different Column using IF AND functions?

I have a table that somewhat looks like this: enter image description here

I am trying to spread the values on column B using an IF-AND function so that it would pull the values from column A until it reaches a new value in the column. I have tried =IF(AND(A2="",A3="",A1<>""),A1,A2) for cell A2, but while the function recognizes the beginning of a new value, it ends up in 0s all in between. enter image description here

How should I adjust the function to be able to fill the cells with corresponding values? I appreciate the help.