Count days based on 3 dates

Hi, I am looking to count the value of dates based on certain criteria.

I have todays date in cell A1. I want to count how many nights stay (Cells I7-9) from Admission date (E7-9) to current date (A1), however it needs to only calculate if there is an admission date (E7-9) and stop calculation if we have a demission date (G7-9). If no admission date, the cell stay blank.

I have worked out the formula to calculate this and it works if there is a demission date and stays blank if no admission date, however I am not getting a current number of days if there is an admission, but no demission yet.

The formula I have in is =IF(ISBLANK($E9),"",($A$1-$E9)-($A$1-$G9)) HELP!!!

TIA
Angie