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:
a=[9,99,999,9999,99999,999999,9999999,99999999,999999999,9999999999,99999999999,999999999999]
n=int(input()); vt=0
if n<=9: print(n)
else:
	for i in a:
		if(i<=n): vt+=1
		else: break;
	m=n-a[vt-1]; ans=0
	while m>0:
		ans+=int(m%10); m/=10
	while a[vt-1]>0:
		ans+=int(a[vt-1]%10); a[vt-1]/=10
	print(ans)