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 Mohammad  {
    public static long S(long l){
        long c = 0;
        while(l != 0){
            c += l%10;
            l /= 10;
        }
        return c;
    }
    public static void Mohammad_AboHasan() throws IOException{
        FastScanner fs = new FastScanner();
        long n = fs.nextLong(), c = 0;
        while(c <= n){
            c *= 10;
            c += 9;
        }
        c /= 10;
        System.out.println(S(c) + S(n-c));
    }
    public static void main(String[] args) throws IOException{
        Mohammad_AboHasan();
    }
    static class FastScanner{
        BufferedReader br;
        StringTokenizer st;
        public FastScanner() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }
        String next() throws IOException{
            while (st == null || !st.hasMoreElements()) {
                    st = new StringTokenizer(br.readLine());
            }
            return st.nextToken();
        }
        int nextInt() throws IOException{
            return Integer.parseInt(next());
        }
        long nextLong() throws IOException{
            return Long.parseLong(next());
        }
        double nextDouble() throws IOException{
            return Double.parseDouble(next());
        }
        String nextLine() throws IOException{
            String s = br.readLine();
            return s;
        }
    }
}