There doesn't seem to be a way to print the flag in this program… or is there? The executable is provided to you for convenience.

main.c b507426debc7a1a4fe9e374de79d81cd 543B
main 41832722eb1c84473bec7f54f25af36c 16K

The judge will run main.c. You must interact with the judge with a solution through the standard input and output streams. Anything the judge outputs will be in your standard input stream, and anything you output to standard output will be forwarded to the judge as input. If your solution successfully causes the judge to print the flag to its standard error stream, you will receive AC. Otherwise, you will receive WA. Note that at no point during the judging will your program receive the flag. Additionally, the judge does not need to exit with an exit code of 0. It can exit with anything.

This problem is from DMOJ Capture The Flag '20. For more details, please view the contest page.