I'm not really logged in as root on my server but I thought root@host would be more recognizable.

root@host:~# strings pronz.txt |grep -o "[^ ]*$" | sort | uniq -c | sort -nr | head
        671 123456
        212 123456789
        111 12345
          75 1234
          72 12345678
          65 1234567
          62 password
          52 1234567890
          49 123
          41 123123