Problem: You are given a positive integer n.

Let S(x) be sum of digits in base 10 representation of x, for example, S(123) = 1 + 2 + 3 = 6, S(0) = 0.

Your task is to find two integers a, b, such that 0 ≤ a, b ≤ n, a + b = n and S(a) + S(b) is the largest possible among all such pairs.

Input

The only line of input contains an integer n (1 ≤ n ≤ 10^{12}).

Output

Print largest S(a) + S(b) among all pairs of integers a, b, such that 0 ≤ a, b ≤ n and a + b = n.

Examples

Input

35


Output

17


Input

10000000000


Output

91

Note

In the first example, you can choose, for example, a = 17 and b = 18, so that S(17) + S(18) = 1 + 7 + 1 + 8 = 17. It can be shown that it is impossible to get a larger answer.

In the second test example, you can choose, for example, a = 5000000001 and b = 4999999999, with S(5000000001) + S(4999999999) = 91. It can be shown that it is impossible to get a larger answer.

Solution (in PYTHON3):

Solution:
class CodeforcesTask1060BSolution:
    def __init__(self):
        self.result = ''
        self.n = 0

    def read_input(self):
        self.n = int(input())

    def process_task(self):
        if self.n < 10:
            self.result = str(self.n)
        else:
            self.result = str(sum([9] * (len(str(self.n)) - 1) +
                              [int(x) for x in str(self.n - int("9" * (len(str(self.n)) - 1)))]))

    def get_result(self):
        return self.result


if __name__ == "__main__":
    Solution = CodeforcesTask1060BSolution()
    Solution.read_input()
    Solution.process_task()
    print(Solution.get_result())