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=(input())
if(int(n)<=10):
	print(n)
else:
	n1=list(n)
	n2=list(n)
	n1[0]=(int(n[0])-1)
	n2[0]=str(int(n[0])-1)
	for i in range(1,len(n)):
		n1[i]=(9)
		n2[i]=str(9)
	k=list(str(int(n)-int("".join(n2))))
	for i in range(len(k)):
		k[i]=int(k[i])
	print(sum(k)+sum(n1))