When I checked the inside of the provided directory, there was a directory and the directory name was '}', so I thought there was a flag, and I tried "ls -R"


At the end, I figured out that there is a flag format, which is KCTF, and programmed a python code that outputs FLAG to make it easier to see.

```python
import os

flag = []
os.chdir("./challenge")

while True:
try :
Dir = os.listdir()[0]
flag += Dir
except IndexError:
flag = flag[::-1]
break
os.chdir(Dir)

print("".join(flag))
```

FLAG : ```KCTF{f0ld3rs_1n51d3_f0ld3rs}```