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 f(a,b):
    res = 0
    for i in a:
        res += int(i)
    for i in b:
        res += int(i)
    return res

n = int(input())

if n<18:
    print(n)
    exit()

elif n<100:
    t=0
    a = n//10
    if n%10!=0:
        t = a*10-1
    else:
        t = n-1
    v = n-t

    res = f(str(t),str(v))
    print(res)
else:
    k = str(n)
    t = "9"*(len(k)-1)
    t = int(t)
    v = n-t
    print(f(str(v),str(t)))