In a fluorescent tube of diameter 3 cm, 8 X 10^18 electrons and 2 X 10^18 positive ions (with a charge of +e) flow through a cross-sectional area

In a fluorescent tube of diameter 3 cm, 8 X 10^18 electrons and 2 X 10^18 positive ions (with a charge of +e) flow through a cross-sectional area each second. What is the current in the tube? The equation I used was: I = A*J (A being cross-sectional surface area and J the charge density)Since There are two different currents (from electrons and positive ions) I added the Charge desities, then found the Area and multiplied these together, but my answer is not correct. What did i do wrong???