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.