# rules about variables
#   must not have spaces, or punctuation
#   must not start with a digit

w__3rt = 3
_ = 4

# traditions about variable names:
#   all lower case
#   not be single letters
#   words are separated by _

square_root_of_seventeen = 17 ** (1 / 2)

# two functions we need: print and input
print(w__3rt)
print()
print(square_root_of_seventeen + 3, w__3rt)

user_input = input('type something ')
print('you typed', user_input)