def ask_pair_of_radii() -> (int, int): input_ok = False while not input_ok: try: r1 = int(input("r1 = ")) r2 = int(input("r2 = ")) input_ok = True return r1, r2 except ValueError as ex: print("Eingabe ist keine Zahl") def main(): outer_radius, inner_radius = ask_pair_of_radii() print(f"Außenradius = {outer_radius} Innenradius = {inner_radius}") if __name__ == "__main__": main()