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(""))
basamak=0
if(n<10):
    print(n)
else:
    n1=n
    toplam=0
    while(n1 > 0): 
        rakam = int(n1 % 10)
        toplam = toplam + 1
        n1 = int(n1 / 10)
    basamak=toplam-1
    
    sayi2=(10**(basamak))-1
    
    n=n-sayi2
    toplami=0
    while(n > 0): 
            rakam = int(n % 10)
            toplami = toplami + rakam
            n = int(n / 10)
    toplami=toplami+basamak*9
    print(toplami)