Find first occurrence of a 0

I would like to find the occurrence of the first 0 or negative number in a column and come up with the number in the adjacent column. For example:

Column A Column B
1 6
2 4
3 12
4 4
5 1
6 0
7 -2
8 -4
9 5

Since the first 0 or negative number is -2 then answer would be 6.