Let's see the file type of the file.
file strings
strings: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 3.2.0, BuildID[sha1]=0cdedfba33422d235dba8c90e00fb77b235f1ff8, not stripped
Using strings on it and save the printout to a file.
strings strings > strings-output.txt
Seemed like a big file to go through. Then i used grep to find pico in the output of strings.That did the job.
strings -d strings | grep "pico"
picoCTF{5tRIng5_1T_7f766a23}