BahnCard Card Number

I have just purchased a BahnCard ONLINE and have a one-sided print-out of my BahnCard. To receive my discount on my DB Train ticket, I am being asked for my BahnCard Card Number. I have put in every single possible number that shows up on the online print-out, but I am continually getting the message: "This card number is invalid." Can someone please tell me where to find my BahnCard Card Number on a one-sided online print out, so that I can complete my DB Train ticket purchase. Help! and Thank you!