/
(((?=.*[A-Z])(?=.*[a-z]))|((?=.*[a-z])(?=.*[A-Z]))|((?=.*[A-Z])(?=.*[0-9]))|((?=.*[0-9])(?=.*[A-Z]))|((?=.*[a-z])(?=.*[0-9]))|((?=.*[0-9])(?=.*[a-z]))|((?=.*[A-Z])(?=.*[a-z])(?=[0-9]))|((?=.*[A-Z])(?=.*[0-9])(?=[a-z]))|((?=.*[a-z])(?=.*[A-Z])(?=[0-9]))|((?=.*[a-z])(?=.*[0-9])(?=[A-Z]))|((?=.*[0-9])(?=.*[A-Z])(?=[a-z]))|((?=.*[0-9])(?=.*[a-z])(?=[A-Z])))^[a-zA-Z0-9]{8,20}$
/
gm