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=int(input())
k=0
def sum(n):
    summ=0
    while n>0:
        summ+=n%10
        n//=10
    return summ
for i in range (0,14,1):
    if n<10**i:
        k=i
        break
a=10**(k-1)-1
l=0
for i in range (1,10,1):
    if n<i*(10**(k-1))+a:
        l=i-1
        break
h=n-(l*(10**(k-1))+a)
a=sum(h)
print((9*(k-1))+l+a)

'''

def sum(n):
    i=12
    k=0
    while i>0:
        k+=n%(10)
        n=n//10
        i-=1
    return k
x=sum(n)
for i in range (0,n+1,1):
    if (sum(n-i)+sum(i))>x:
        x=(sum(n-i)+sum(i))
print(x)
'''