#!/usr/bin/python3
# py calc
alphanumeric = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"

while True:
    payload = input("I'll crunch your number, not letters!\n")
    if (any(c in alphanumeric for c in payload)):
        print("NO!")
        continue
    try:
        print(eval(payload, {'__builtins__': {}}, {}))
    except Exception as e:
        print("something went wrong")
        print(e.__class__)