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())
maxx = 0
N = len(str(n))
n1 = ''
dem = 0
for i in range(N-1):
    n1 = n1 + '9'
    dem += 9
tam = n1
for i in range(9,-1,-1):
    tam = str(i) + tam
    if int(tam) <= n:
        dem += i
        n1 = tam
        break
    else:
        tam = n1
n2 = n -int(n1)
while n2 > 0:
    dem += n2%10
    n2 = n2//10
print(dem)