1 num = int(input("请输入一个自然数:"))
 2 nums = []
 3 for i in range(1,a):
 4     for j in range(1,a):
 5         nums.append(i*j)
 6 if a in nums:
 7     
 8     print("不是质数!!")
 9 
10 else:    
11     print("是质数!!")