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 S(a):
  return sum([int(x) for x in str(a)])

def suman(a):
  res = 0
  suma = []
  for i in range((a + 1) / 2):
    x, y = i, abs(a - i)
    ans = S(x) + S(y)
    if res < ans:
      res = ans
      suma = [[x, y]]
    elif res == ans:
      suma.append([x, y])
  print(res)
  for i in suma:
    print(i)

# suman(input())

kumar = input()
if len(kumar) == 1:
  print(kumar)
else:
  n = len(kumar)
  a = int(str(int(kumar[0]) - 1) + '9' * (n - 1))
  b = int(kumar) - a
  print(S(a) + S(b))