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:
def ii():
    return int(input())
def mi():
    return map(int, input().split())
def li():
    return list(mi())

s = list(map(int, list(input().strip()[::-1])))
n = len(s)

carry = 0
a, b = [], []
for i in range(n):
    d = s[i] - carry
    if d == 9 or i == n - 1:
        a.append(d)
        b.append(0)
        carry = 0
    else:
        d0 = 9
        d1 = 10 + d - 9
        a.append(d0)
        b.append(d1)
        carry = 1

ans = sum(a) + sum(b)
print(ans)