#!/usr/bin/perl -w

use constant minUC => 3;
my $min = 3;
my $test = "AAAAAA";

    my @chars = (split //, $test);
    my $Rep = 0;
    foreach my $c ( @chars)
    {
        $Rep++  if  ($test =~ /$c{3,}?/) ;       # this works
#    $Rep++ if ($test =~ /$c{$min,}?/) ;   #     no work; 
#    $Rep++ if ($test =~ /$c{minUC,}?/) ; #nor does using a named constant   
    }