while True:
    try:
       in_num = int(input())
       i=2
       while(in_num/i>i-1):
            if in_num % i == 0:
                print(i,end=" ")
                in_num = in_num /i
            else:
                i = i+1
       print(int(in_num),end=" ")

    except:
        break
python两层循环解决