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 PYTHON):

Solution:

st = str(raw_input())
p = ''
flag = 0
for index, c in enumerate(reversed(st)):
    if index != len(st)-1:
        if c == '0':
            p += str(9)
            flag = 1
            continue
        elif c == '9':
            p += str(9)
            continue 
        now = int(c)+10-flag-9
        flag = 1 if now != 0 else 0
        p += str(now)
    else:
        p += str(int(c)-flag)
p = int(p[::-1])
pp = int(st) - p
ans = 0
while p != 0:
    ans += p % 10
    p //= 10
while pp != 0:
    ans += pp % 10
    pp //= 10
print ans