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()

l = len(n)
s= 0
if int(n) > 10:
    temp = int(n[0]) - 1
#print(len(n))
    new_n = str(temp)
    chin = '9'*(int(l)-1)

    new_n = new_n +  chin

    for i in new_n:
        s = s + int(i)

    conlai = int(n) - int(new_n)

    for i in str(conlai):
        s = s+ int(i)
    print(s)
else:
    print(int(n))

'''
if n%2 == 0:
    a,b = str(k-1),str(k+1)
    for i in a:
        s = s + int(i)
    for j in b:
        s = s+ int(j)
else:
    a,b = str(k),str(k+1)
    for i in a:
        s = s + int(i)
    for j in b:
        s = s + int(j)
print(a,b)

print(s)
'''