could you please help how to run this file on command prompt

[m123]

code is as shown below, saved as ynb.py

def get_cube_root(num):
	return num ** (1. / 3)

i tried to run in command prompt

Error:
C:\Users\s\Documents>python -c get_cube_root(27)
ImportError: No module named site

C:\Users\s\Documents>python -c 'from footbar import *; print get_cube_root(27)
ImportError: No module named site

C:\Users\s\Documents>python ynb.py
ImportError: No module named site

C:\Users\s\Documents>ynb.py

C:\Users\s\Documents>python ynb.py
ImportError: No module named site

C:\Users\s\Documents>print ynb.by
Unable to initialize device PRN

any suggestion