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:
n = input()
final = 0
if len(n) > 2:
    if n[0] != '1':
        ln = len(n)
        maxArr = ['0']
        maxArr[0] = str(int(n[0])-1)
        for i in range(len(n)-1):
            maxArr.append(9)
        max = int(''.join(str(e) for e in maxArr))
        min = str(int(n)-max)
        for i in maxArr:
            final+=int(i)
        for i in range(len(min)):
            final+=int(min[i])
        print(final)
    else:
        ln = len(n)
        maxArr = ['9']
        for i in range(len(n)-2):
            maxArr.append(9)
        max = int(''.join(str(e) for e in maxArr))
        min = str(int(n)-max)
        for i in maxArr:
            final+=int(i)
        for i in range(len(min)):
            final+=int(min[i])
        print(final)
else:
    n = int(n)
    final=[]
    def sum_digits(digit):
        return sum(int(x) for x in digit if x.isdigit())
    for i in range(int(n/2)+1):
        digit=str(i)+str(n-i)
        final.append(sum_digits(digit))
    max=int(max(final))
    print(max)