#!/usr/bin/perl
use strict;
use warnings;
my $count = 0;
while (<DATA>){
    $count++ while m/[a-zA-Z]\w*/g;
}
print $count, $/;

__DATA__
Usage: perl [switches] [--] [programfile] [arguments]
  -0[octal]       specify record separator (\0, if no argument)
  -a              autosplit mode with -n or -p (splits $_ into @F)
  -C[number/list] enables the listed Unicode features
  -c              check syntax only (runs BEGIN and CHECK blocks)
  -d[:debugger]   run program under debugger