How to fix error SyntaxError: Non-UTF-8 code starting with '\x90' in file count.exe?

Question

Python

I did not find any advice on the Internet that helped me. It was written that when converting .py to .exe, there may be Cyrillic. I checked the path, and did not find a single Russian letter. I have do.py file. And it launches another count.exe file, so when it launches this file it gives such an error. But if you run the file separately, then everything works

File "count.exe", line 1
SyntaxError: Non-UTF-8 code starting with '\x90' in file count.exe on line 1, but no encoding declared; see http://python.org/dev/peps/pep-0263/ for details