use strict;
use warnings;
print "A-B =~ /A.+B/ --> ";
print "worked" if "A-B" =~ /A.+B/;
print "\n";
print "A-B =~ /A.*B/ --> ";
print "worked" if "A-B" =~ /A.*B/;
print "\n";
print "AB =~ /A.+B/ --> ";
print "worked" if "AB" =~ /A.+B/;
print "\n";
print "AB =~ /A.*B/ --> ";
print "worked" if "AB" =~ /A.*B/;
print "\n";
##```
##
A-B =~ /A.+B/ --> worked
A-B =~ /A.*B/ --> worked
AB =~ /A.+B/ -->
AB =~ /A.*B/ --> worked
```