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.util.*; 
import java.io.*;
import java.math.*;

public class Main3
{ 	

	public static void main(String[] args)throws Exception
	{ 	
	    Reader reader = new Reader();
		reader.readLine();
		long n = reader.readLong(0);
		int numOfDigit =0;

		for (long i=n;i != 0;i /= 10)
			++numOfDigit;
			
		int sum = --numOfDigit*9;
		n = n-(long)(Math.pow(10,numOfDigit))+1;
		
		while(n>0)
		{
			sum += n%10;
			n/=10;
		}
		
		System.out.println(sum);
		reader.close();
	}
}

class Reader
{     
    private BufferedReader reader; 
    private String line[];     

    public Reader()     
    {         
        reader = new BufferedReader(new InputStreamReader(System.in));     
    }     

    public String[] getLine()     
    {         
        return line;     
    }     

    public boolean readLine()     throws IOException 
    {         
        String str = reader.readLine();
        if (str == null || str.isEmpty())
            return false;
        line = line = str.split(" ");
        return true;
    }    

    public List<Integer> getIntegersList()
    {
        List<Integer> res = new ArrayList<>();
        for (String str:line)
            res.add(Integer.parseInt(str));
        return res;

    }

    public int readInt(int pos)throws IOException     
    {         
        return Integer.parseInt(line[pos]);     
    }     

    public double readDouble(int pos)throws IOException     
    {         
        return Double.parseDouble(line[pos]);     
    }     

    public long readLong(int pos)throws IOException 
    {         
        return Long.parseLong(line[pos]); 
    }     

    public String readString(int pos)throws IOException     
    {         
        return line[pos];     
    }     

    public void close()throws IOException 
    {         
        reader.close();     
    }
}