I have a spreadsheet containing a cell with comments in the following format
to explain changes in value:

1mm mkt, (3.23mm) jnl, 115k px

The comments might change but "mm" will always represent 1,000,000, "k" will
always represent 1,000 and negative values will be in parenthesis.

Is it possible to write a function that removes the comments, converts the
values to their real values and sums them? In the example above the
function should produce a value of negative 2,115,000.

Thank you.