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:
MX = 13

n = input()
while len(n) < MX:
    n = '0' + n

n = n[::-1]

best = 0

for mask in range(1 << MX):
    if (1 << 12) & mask:
        continue

    ans = 0
    bad = False

    for i in range(MX):
        has = int(((1 << i) & mask) != 0)
        has_prev = 0 if i == 0 else (((1 << (i - 1)) & mask) != 0)

        cur = int(n[i]) + has * 10 - has_prev
        bad |= cur < 0
        bad |= cur == 19

        ans += cur

    if not bad:
        best = max(ans, best)


print(best)