Leetcode Count and Say

class Solution(object):
    def countAndSay(self, n):
        """
        :type n: int
        :rtype: str
        """
        s = "1"
        for i in range(0,n-1):
            current = ""
            count = 0
            ctstr = ""
            for j in s:
                if ctstr == j:
                    count += 1
                else:
                    if count != 0:
                        current += str(count) + ctstr
                        count = 1
                        ctstr = j
                    else:
                        count = 1
                        ctstr = j
            current += str(count) + ctstr
            s = current
        return s
solution = Solution()
print(solution.countAndSay(5))