need to populate cell with SUM of negative numbers from column of mixed neg and pos number

Hello everyone,

Hoping someone can help me out with this... it's probably pretty simple for a lot of the pros on this board.

I have a column in a budget spreadsheet in which the cells are formatted as currency. Some of the cells contain positive numbers, some contain negative numbers. What I'm hoping to do is have excel find all the negative numbers in that column, add them together and populate a cell in a different column with the result. Specifically, as an example, go through column J and find all neg numbers, SUM them and put the result in cell F70.

Thanks in advance for any help you guys can offer. Much appreciated