Enter the flag:
Claim Command:
/challenge claim flag:<flag>
Here's a linux program compiled by another program I wrote, it should be fairly unintuitive to reverse engineer so good luck!
https://cdn.discordapp.com/attachments/631618075254325257/759334352886169640/a.out
Since I'm nice, here's the source code: https://gist.github.com/simmsb/28c165087b301fcce234c1533861421e
And here's the source code of the compiler: https://github.com/simmsb/some-scheme-compiler