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 numsum(x):
    sum = 0
    while(x!=0):
        sum = sum + x % 10
        x = x // 10
    return sum

inp = int(input())
futurereference = inp
holder = inp
b = 1

while(inp!=0):
    current = (inp-1) * b + (b-1)
    if(numsum(current))>=(numsum(holder)):
        holder = current
    inp = inp//10
    b = b * 10

m = holder
n = futurereference - holder
#print(m,n)

digitsum = 0
for digit in str(m):
    digitsum = digitsum + int(digit)
#print(msum)
for digit in str(n):
    digitsum = digitsum + int(digit)
print(digitsum)