How to fix Notepad++ NppExec Error

Question

I'm trying to fix a error in Notepad++, I'm using NppExec plugin in Notepad++ and trying to execute my code. Whenever I click Plugins, NppExec, Execute, a window popups. Then I type this:

print("Hello World")

and press 'OK', a error line like this appears:

print("Hello World!")
about to start a child process: "print("Hello World!")"
`CreateProcess() failed with error code 2:`  
The system cannot find the file specified.           

How should I fix this? Am I using it in the wrong way? Or is there any way to fix this? [Sorry if I hadn't explained well]