You have an Azure subscription that contains the resources shown in the following table.

You plan to deploy an Azure Virtual Network NAT gateway named Gateway 1. The solution must meet the following requirements:

• VM1 will access the internet by using its public IP address.

• VM2 will access the internet by using its public IP address.

• Administrative effort must be minimized.

You need to ensure that you can deploy Gateway1 to Vnet1.

What is the minimal number of subnets that Vnet1 must have?