Can there exist two Dalai Lamas at one instance of time?

I am developing an application which calculates peoples age/ birthdays. In this app I have one entry for the Dalai Lama. My understanding is that its the 14 Dalai Lama who is alive right now. So a concern is raised that should I use the name Dalai Lama or 14 Dalai Lama I want to know if there can be two Dalai Lamas alive at the same instance if this is not true I can simply use the name Dalai Lama Please shed light on this aspect!