# -*- coding:utf-8 -*-
class Solution:
    def NumberOf1Between1AndN_Solution(self, n):
        # write code here
        cnt = 0
        while n > 0:
            string = str(n)
            chars = list(string)
            for i in range(len(chars)):
                if chars[i] == '1':
                    cnt += 1
            n -= 1
        return cnt