#!/usr/bin/perl
use threads;
use threads::shared;
my $n : shared;

$a = gets();
print $a . "\n";

sub gets {
   $thr = 10;
   $n = 0; 
   for(0..$thr) {
       $trl[$_] = threads->create(\&gets1);
   }
   for(0..$thr) {
       $trl[$_]->join;
   }
   sub gets1 {
      $| = 1;
      $ii = "";
      while ($n < 10) {
            { lock($n);
            $n++; }
            $ii .= $n; 
            print $ii . "\n";
      }
      return $ii;
   }
}