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 chan(x,f):
    n=0
    p=x
    while(True):
        if (int(str(n)+x)>f):
            return p
        p=str(n)+x
        n=n+1
        if(n>9):
            return x
    
n=int(input())
x='9'
f=n
if(n>9):
    while (int(x+'9')<=n):
        x=x+'9'
    
    x=chan(x,n)
    f=sum(map(int,(list(x)))) 
    x=str(n-int(x))
    f=f+sum(map(int,(list(x)))) 
print(f)