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:
a = int(input())
if a > 9:
    d = a
    i = 0
    while d > 0:
        y = d
        d = d // 10
        i += 1
    w = ((a // (10 ** (i - 1)))) * (10 ** (i - 1)) - 1
    y = a - w

    def sum123(a):
        global sum, s
        sum = 0
        while a > 0:
            s = a % 10
            sum += s
            a = a // 10
        return sum


    sumend = sum123(w) + sum123(y)
    print(sumend)
else:
    print(a)