python3计算鸡兔同笼的程序，但会出现小数，怎么样修改能让它如果算出小数就print("此题无正确答案")？

Question

def 鸡的只数(总只数,总脚数):
      return (4*总只数-总脚数)//2
def 兔的只数(总只数,总脚数):
      return (总脚数-2*总只数)//2
总只数= int(input("请输入鸡和兔共有几个头："))
总脚数= int(input("请输入鸡和兔共有几只脚："))
print("鸡的只数=",鸡的只数(总只数,总脚数))
print("兔的只数=",兔的只数(总只数,总脚数))

Answer 1

# -*- coding:utf-8 -*-
import sys

def chickenNum(totals, foots):
    if (4 * totals - foots) % 2 == 1 or (foots - 2 * totals) % 2 == 1:
        sys.exit('此题无正确答案')
    return (4 * totals - foots) // 2


def rabbitNum(totals, foots):
    if  (4 * totals - foots) % 2 == 1 or (foots - 2 * totals) % 2 == 1:
        sys.exit('此题无正确答案')
    return (foots - 2 * totals) // 2

totals = int(input("请输入鸡和兔共有几个头："))
foots = int(input("请输入鸡和兔共有几只脚："))
print("鸡的只数=", chickenNum(totals, foots))
print("兔的只数=", rabbitNum(totals, foots))