Three boys Conan, Genta and Mitsuhiko were out hiking one day and they came across a cave. They went inside the cave for a while and when they exited, Conan was missing. Genta and Mitsuhiko went back inside the cave to look for him. On the walls were numbers in green paint that they hadn't noticed beforehand. The numbers were as follows:
4 8 20 21 10 27 36 23 22
After they wrote the numbers in a notebook, they came across a letter written in the same green paint. It read:
Oh, it bothers me to write letters like this. Of how I came across this event I am not aware. However, things must be done. I have written the numbers on the walls. You must use these numbers to find my hiding spot. Good Luck.
- Edogawa Conan
How should they find him?