Password Regex dynamic checking opposite of code

I need to setup password requirements. Minimum length can be configured.

But i need to add  

Must Contain upper or lower case.

I am trying this with Regex Requirement.  /[A-Za-z]+/     logically that's working.

But

Looks like Regex works like 'characters that are not allowed' instead matching a Regex.

So dynamic checking is opposite of my code.

 

As per screenshot, when regex match it show   but when it don't match it show right mark.

Any Lead ?

Thanks