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:
def sumnum(x):
	z=str(x)
	l=len(z)
	d=0
	m=0
	for i in range (l):
		m=int(z[i])
		d+=m
	return d
	
n=int(input())
f=9
c=True
i=1
if n<9:
	maks=n
else:
	while c:
		if n>=f:
			f+=9*(10**i)
			i+=1
		else:
			c=False
	f-=9*(10**(i-1))
	maks=sumnum(f)+sumnum(n-f)
print(maks)