use strict;
use warnings;

my %h;

while (<DATA>)
{
    $h{$_}++ for map { lc } grep { /^[a-zA-Z]+$/ } split /\W+/;
}

for (sort keys %h)
{
    printf "%10s %05d\n", $_, $h{$_};
}
__DATA__
This line contains garbag3, and words!
This line does not.