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 13f717ca276bdad1189b3a19ee4d0735 513B
main 4e71566326ad633b4ce5d73ac14eebb4 17K

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.