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.*;
import java.util.*;
public class Maximum_sum {

	/**
	 * @param args
	 * @throws Exception 
	 * @throws NumberFormatException 
	 */
	public static void main(String[] args) throws NumberFormatException, Exception {
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));

String s=br.readLine();

String s2=(s.charAt(0)-'0')-1+"";
//System.out.println(s2);


for(int i=1;i<s.length();i++){
	
	s2+="9";
	
	
}

//System.out.println(s2);

long ans1=Long.parseLong(s)-Long.parseLong(s2);
String s3=""+ans1;
long ans3=0;
long ans2=0;

for(int i=0;i<s2.length();i++){
	
	ans2+=(s2.charAt(i)-'0');
	
	
}
for(int i=0;i<s3.length();i++){
	
	ans3+=(s3.charAt(i)-'0');
	
	
}
System.out.println(ans3+ans2);



	}

}