Rearrange what we receive from the server in 41x21 matrix and we get a [QR code](https://github.com/CTF-STeam/ctf-writeups/tree/master/2021/UgraCTF/qr.txt).
![QR](https://github.com/CTF-STeam/ctf-writeups/raw/master/2021/UgraCTF/qr.png)
Flag: `ugra_soviet_technologies_are_eternal_ee7c486eb987`