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:
/*package whatever //do not write package name here */

import java.io.*;
import java.util.*;
public class S {
	public static void main (String[] args) {
		Scanner in=new Scanner(System.in);
		long n=in.nextLong();
		int p=(int)Math.floor(Math.log10(n))+1;
		//System.out.print(p);
		long c=(long)n%(long)Math.pow(10,p-1);
		long a=n-c-1;
		long b=n-a;
		//System.out.print(a+" "+b);
		long res=0;
		while(a!=0)
		{
		    res=res+a%10;
		    a=a/10;
		}
		while(b!=0)
		{
		    res=res+b%10;
		    b=b/10;
		}
		System.out.print(res);
	}
}