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:
x = input().split(" ")
n = eval(x[0])
i=0
while n//(10**i)!=0:
    i+=1
if i==1:
    print(n)
else:
    s=0
    temp = 0
    for j in range(i):
        if j==0:
            if n%10==9:
                s+=9
            else:
                s+=10+(n%10)
                temp=1
        elif j ==i-1:
            s+=n-temp
        else:
            if n%10==0:
                s+=10-temp
                if temp==0:
                    temp=1
            elif n%10==9 and temp==0:
                s+=9
            else:
                s+= 10+(n%10)-temp
                temp=1
        n= (n-(n%10))/10   
    print((int)(s))