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:
a = input()
# a = list(a)
a = [int(x) for x in list(a)]
ans = 0
borrow = 0
while a:
    if(len(a) == 1):
        ans += a[0]
        del a[0]
        break
    for el in a:
        if(el == 0):
            del a[0]
        else:
            break
    if(len(a) == 0):
        break
    if(a[len(a) - 1] != 9):
        ans += a[len(a) - 1] + 10
        borrow = 1
    else:
        ans += 9
    del a[len(a) - 1]
    for x in range(len(a) - 1, -1, -1):
        if(a[x] != 0):
            a[x] -= borrow
            borrow = 0
            break
        elif(borrow):
            a[x] = 9
print(ans)