You need to design an IP address plan for an upcoming GKE cluster in your VPC. This will be a VPC-native cluster using the default Pod IP range allocation. All required VPC subnets and their corresponding IP ranges must be pre-provisioned before cluster creation. The cluster will start with one node but may scale up to a maximum of three nodes. You aim to allocate the smallest possible number of Pod IP addresses.

What subnet mask should you assign to the Pod IP address range?