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 JAVA):

Solution:
import java.io.PrintWriter;
import java.util.*;
import java.util.Formatter;
public class Main {
	
	public static int gcd(int a,int b)
	{
		int r;
		
		while(b>0)
		{
			r=a%b;
			a=b;
			b=r;
		}
		
		return a;
	}
	
	public static int dig(long n)
	{
		int sum=0;
		while(n>0)
		{
			sum+=n%10;
			n/=10;
		}
		return sum;
	}
	
	
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		PrintWriter out = new PrintWriter(System.out);
		int i,j,b,c,k,d,l,max_=-1,cnt=0,ans=0;
	

		long n,m;
		
		n=sc.nextLong();
		
		m=0;
		
		while(10*m+9<=n)m=10*m+9;
		
		System.out.println(dig(m)+dig(n-m));
		
	} 

}