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:
m = int(input())
mm = m
ms = []
c = 0
a=1
b=1
if m < 10:
    print(m)
    exit(0)
for x in range(1,len(str(m)),+1):
    ms.append('9')
if str(m)[0] != '1':
    ms.insert(0,str(int(list(str(m))[0])-1))
ms_int = int(''.join(ms))
b_int = m-ms_int
wyn = 0
for x in ms:
    wyn+=int(x)
for x in list(str(b_int)):
    wyn+=int(x)
print(wyn)