A simple google search reveals that space seperated strings are actually sha256 and md5 hashes of different single characters.
Run the following python script to replace hashes with their characters.
```
import string
import hashlib

str="challenge_string_here"
for i in string.printable:
str=str.replace(hashlib.md5(i.encode()).hexdigest(),i)
str=str.replace(hashlib.sha256(i.encode()).hexdigest(),i)
str=str.replace(" ","")
print(str)
```
Look for "F#" in the resulting string.