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=input()
s=list(n)
a=""
if s.__len__()>1:
    if s[0]==1:
        for i in range(s.__len__()-1):
            s[i]=9
    else:
        s[0]=int(s[0])-1
        for i in range(s.__len__()):
            if(i>0):
                s[i]=9

    for i in range(s.__len__()):
        if s[i]==0:
            continue
        else:
            a+=str(s[i])

    a=int(a)
    b=int(n)-a

    ans=int(0)
    while a>0:
        ans+=a%10
        a//=10
    while b>0:
      ans+=b%10
      b//=10
    print(ans)
else :
    print(s[0])