$ perl -E '
    my ($x, $y, $c, $p) = qw{AxAAxAAAxAAAA AA 0 0};
    $c++, $p += 2 while ($p = index $x, $y, $p) > -1;
    say $c;
'
4

##</code><code>##

$ perl -E '
    my ($x, $y, $c, $p) = qw{AxAAxAAAxAAAA AA 0 0};
    $c++, $p++ while ($p = index $x, $y, $p) > -1;
    say $c;
'
6