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 sumd(x):
    d=0
    while x:
        d+=(x%10)
        x/=10
        x=int(x)
    return d


n=int(input())


def contains0(x):
    while x:
        if x%10==0: return True
        x/=10
        x=int(x)
    return False

def solve(n):
    if n<=10:
        return n
    
    x=9
    while (10*x + 9)<n:
        x=(10*x)+9
    y=n-x
    return sumd(x)+sumd(y)

print(solve(n))