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:
def sum_digits3(n):
   r = 0
   while n:
       r, n = r + n % 10, n // 10
   return r
a = input()
n = int(a)
l = len(a)
if l==1:
    print(n)
else:
    b = "1"
    b+="9"*(l-1)
    sum_b = 9*(l-1)+1
    if(a[0]=='1'):
      b="9"*(l-1) 
      sum_b = 9*(l-1)
    b = int(b)
    a = n-b;
    print(sum_digits3(a)+sum_b)