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:
'''
method:
always use nines for `a`, and then
match with corresponding digit for `b`
 - special case last digit as can't carry

e.g.
199
 14
---
203

'''
n = input()
carry = 0
output = 0
#reverse iterate from last to second digit
for d in map(int, n[:0:-1]):
    if d == 9 and carry == 0:
        output += 9
        carry  = 0
    else:
        output += 9 + d + 1 - carry
        carry = 1
output += int(n[0]) - carry
print(output)