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 main ():
	n = int(input())
	ans = n
	x = 1
	n1 = 1
	t = 0
	k = 0
	if n<10:
		x = 1
	else:
		for u in range (1000):
			n /= 10
			x+=1
			if n < 10:
				break
	x -=1
	for i in range(x):
		n1 *= 10
	n1 -= 1
	n2 = ans - n1
	for i in range (n1):
		t+= n1%10
		n1 = n1//10
		if n1<10:
			t+=n1
			break
	for i in range(n2):
		k+= n2%10
		n2 = n2//10
		if n2<10:
			k+=n2
			break
	print(t+k)





	
main()