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 PYTHON):

Solution:
num = input()

if num<=10:
    print num
    exit()
pair1 = int(str(num)[1:])+1
pair2= num - pair1


def get_pairs(num):
    other_par = 0
    while num%10 != 9 :
        other_par +=1
        num = num - 1
    return num, other_par

def sum_digit(num):
   pairs_list = [int(i) for i in str(num)]
   return sum(pairs_list)


#par1, par2 = get_pairs(num)
#print pair1, pair2
print sum_digit(pair1) + sum_digit(pair2)