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 makeNine(num):
    sizer = len(num)-1
    newNum = ""
    for i in range(sizer):
        newNum += "9"
    return int(newNum)

def main():
    n = int(input())
    i = int(n/2)
    if(n > 18):
        numA = str(i)
        i = makeNine(str(n))
        numA = str(i)
        j = n - i
        numB = str(j)
        sumA = 0
        sumB = 0
        for num in numA:
            sumA += int(num)
        for num in numB:
            sumB += int(num)
        total = sumA + sumB
        print(total)
    else:
        print(n)
        
main()