Your company is deploying a set of internet-facing virtual machines in Azure. The security team requires that all outbound and inbound traffic use a contiguous, predictable block of static public IPv4 addresses so that a partner can allowlist the range in their firewall. You decide to provision an Azure Public IP Prefix. The partner needs exactly 12 static public IP addresses to be covered by a single allowlisted CIDR range. What is the smallest public IP prefix size you can request to satisfy this requirement?