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.*;

/*

*/

public class Main{

    public static long[] digits(long num){
        long[] ans=new long[13];
        int temp=12;
        while (num>0){
            ans[temp]=num%10;
            num/=10;
            temp--;
        }
        return ans;
    }
    public static void main(String[] args) throws IOException {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw=new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
        StringTokenizer st=new StringTokenizer(br.readLine());
        long n=Long.parseLong(st.nextToken());
        long[] digits=digits(n);
        int index=0;
        for(int i=0;i<13;i++){
            if(digits[i]>0){
                index=i;
                break;
            }
        }
        long ans=0;
        int i=12,start=12;
        while (i>=index&&digits[i]==9){
            ans+=9l;
            i--;
            start--;
        }
        if(start==index){
            ans+=digits[i];
            i--;
        }
        for(;i>=index;i--){
            if(i==start){
                ans+=(digits[i]+10);
            }else if(i==index){
                ans+=(digits[i]-1);
            }else {
                ans+=(digits[i]+10-1);
            }
        }
        pw.println(ans);


        pw.close();
    }
}