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 = int(input())
num1 = 10 ** (len(str(n+1))-1) - 1
num2 = n - num1
num1 = [int(x) for x in list(str(num1))]
num2 = [int(x) for x in list(str(num2))]
print(sum(num1) + sum(num2))
# num1 = ((n+1) // 10) * 10 - 1
# num2 = [int(x) for x in list(str(n - num1))]
# num1 = [int(x) for x in list(str(num1))]
# print(sum(num1) + sum(num2))

# 99 -> 99
# 100 -> 99 + 1 = 19     
# 
# 99 -> 99
# 100 -> 99
#70 = 69 + 1