Quickset has plenty of limitations built-in … so that it sanitizes most of errors inexperienced users might do. Your case is non-trivial and you should use “regular” winbox section to configure things. And don’t use quickset on said router ever again.
Or if you’d enter it using WinBox/WebFig, it would be xxx.xxx.245.134/30 for Address (that’s all, you don’t put anything in Network) and xxx.xxx.245.133 as gateway.