use strict;
use warnings;

my ($input, $str, @str, $t);

$input .= chr(97 + int rand 26) for 1..100000;
for (1..100000) {
    $str = '';
    $str .= chr(97 + int rand 26) for 1..10;
    push @str, $str;
}
$t = time();
for (@str) {
    print "$_\n" if index($input, $str) != -1;
}
print time() - $t;