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 sum_digit(a):
    k=a
    dem=0
    while k>0:
        x=k%10
        dem+=x
        k=int(k/10)
    return (dem)
ch=input()
n=int(ch)
ch=str(n)
if len(ch)>1:
    n1=str(int(ch[0])-1)
    if n1=='0':
        n1=''
    for i in range(len(ch)-1):
        n1+='9'
    x=int(n1)
    y=n-x
    print (sum_digit(x)+sum_digit(y)) 
else:
    print (n)