Do I need 1 zone or 2 zone

I live on the edge of Burnaby and Vancouver near boundary. I have to take a bus to a sky train in Vancouver to work in Vancouver and then I take the sky train in Vancouver to Nanaimo or Joyce station and then take the bus back to Burnaby.

As I’m crossing two zones, do I need two zones or is it a one zone because I only use the sky train in Vancouver?

Thank you!