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:
s=str(input())
if len(s)==1:
    print(s)
    exit()
flag=False
summ=0
chek=0
is9=True
for i in range(1,len(s)):
    chek=1
    if int(s[-i])==9 and is9==True:
        summ-=10
        chek=0
    else:
        is9=False
    a=10+int(s[-i])-chek
    flag=False
    chek=1
    n=a//2
    nn=a-n
    summ+=(n+nn)
summ+=int(s[0])
print(summ)