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:
from math import log2
n = input()
maxs = 0
if int(n) < 10: print(n)
else:
    for i in range(2**(len(n)-1)):
        tru = [int(j) for j in ("0"*(len(n)-len(bin(i))+1) + bin(i)[2:])]
        s = int(n[0]) - tru[0]
        for j in range(1, len(tru)+1):
            if j != 1 and n[-j] == "9" and tru[1-j]: pass
            elif n[-j] == '9' and tru[-j]:
                s = 0
                break
            if j == 1:
                if tru[-1] == 0: s += int(n[-1])
                else: s += int(n[-1])+10
            else:
                if tru[1-j]: c = int(n[-j]) - 1
                else: c = int(n[-j])
                if tru[-j]: s += 10+c
                else: s += c
        if s > maxs:
            maxs = s
            maks = tru
    print(maxs)
    #print(tru)