class Solution:

    def countAndSay(self, n: int) -> str:

        # 第一个值直接赋予

        pre_num = ""

        for i in range(1,n):

            # 用next_num 记录当前序列,num为前一个序列的第一个值

            next_num,num,count="",pre_num[0],1

            for j in range(1,len(pre_num)):

                # 如果num和前一个序列的下一个值相等，则将count +1

                if num==pre_num[j]:

                    count+=1

                else:

                # 如果不等，将当前count +num 写入next_num,并将count置为1，

                # num取 当前pre_num的值

                    next_num += str(count) + num

                    count =1

                    num =pre_num[j]

            next_num += str(count) + num

            pre_num = next_num

        return pre_num