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 inf,sqrt,floor,ceil
from collections import Counter,defaultdict,deque
from heapq import heappush as hpush,heappop as hpop,heapify as h
from operator import itemgetter
from itertools import product
from bisect import bisect_left,bisect_right


#for _ in range(int(input())):
n=input()
ans=''
d='9'
while len(ans)<len(n):
    if int(d+ans)<=int(n):
        ans=d+ans
    else:
        d=str(int(d)-1)
if ans[0]=='0':
    ans=ans[1:]
another=str(int(n)-int(ans))
x1,x2=0,0
for v in ans:
    x1+=int(v)
for v in another:
    x2+=int(v)
print(x1+x2)