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:
//created by Whiplash99
import java.io.*;
import java.util.*;
public class B
{
    private static long sum(long N)
    {
        long s=0;
        while (N>0)
        {
            s+=N%10;
            N/=10;
        }
        return s;
    }
    public static void main(String[] args) throws Exception
    {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));

        int i;

        long N=Long.parseLong(br.readLine().trim());
        char[] str=(N+"").toCharArray();
        int len=str.length-1;

        long num1=0;
        for(i=0;i<len;i++) num1=num1*10+9;

        String str2=(num1==0)?"":(num1+"");
        str2=(char)(str[0]-1)+str2;

        num1=Long.parseLong(str2);
        System.out.println(sum(num1)+sum(N-num1));
    }
}