This challenge consists of 999 binaries, each of with accepts a single character and prints either "Success" or "Nope" if the character was right or wrong, respectively. 
As someone who likes angr, I decided this would be a quick way to solve. I wrote a very simple angr script that symbolically executes each binary and looks for the word "Success" in the output, then prints the input:
```import angrimport sysimport logging
logging.getLogger('angr').setLevel(logging.CRITICAL)
result = ""
def should_abort(state):    stdout_output = state.posix.dumps(sys.stdout.fileno())    return "Nope" in stdout_output
def is_successful(state):    stdout_output = state.posix.dumps(sys.stdout.fileno())    return "OK" in stdout_output
for i in range(999): # ifor each binary    idx = i + 1 # lazy :)    progname=str(idx).zfill(3) + ".c.out"    project = angr.Project(progname)    state = project.factory.entry_state()    simgr = project.factory.simgr(state)    simgr.explore(find=is_successful, avoid=should_abort)    if simgr.found:        solution_state=simgr.found[0]        result += str(solution_state.posix.dumps(sys.stdin.fileno()))        print(result)    else:        raise Exception("no solution found for {}".format(progname))```
We get way more output than is wanted, but just output to a file and grep for RITSEC and you'll get the flag!