The challenge is the following,
We are also given the file anthem.flag.txt.
I viewed the contents of the file, which contained a very long text.
I counted the words using,
$ wc -w anthem.flag.txt
Which showed that there was 19139 words.
I know the flag format is picoCTF{xxx}, so I decided to grep it using,
$ cat anthem.flag.txt | grep "picoCTF"
Which revealed the flag.
Therefore, the flag is,
picoCTF{gr3p_15_@w3s0m3_4554f5f5}