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.StringTokenizer;
import java.util.stream.LongStream;


public class Main {


  private void solve(InputReader in, PrintWriter out) {
    long n = in.nextLong();
    if (n < 10){
      out.println(n);
      return;
    }
    String s = String.valueOf(n);
    String[] arr = s.split("");
    for (int i = 1; i < arr.length; i++) {
      arr[i] = "9";
    }
    StringBuilder res = new StringBuilder();
    arr[0] = String.valueOf(Integer.parseInt(arr[0]) - 1);
    if (arr[0].equals("0")) {
      for (int i = 1; i < arr.length; i++) {
        res.append(arr[i]);
      }
    } else {
      for (int i = 0; i < arr.length; i++) {
        res.append(arr[i]);
      }
    }
    long a = Long.parseLong(res.toString());
    out.println(sum(a) + sum(n - a));

  }

  private long sum(long n) {
    long res = 0;
    String[] s = String.valueOf(n).split("");
    for (String string : s) {
      res += Integer.parseInt(string);
    }
    return res;
  }

  public static void main(String[] args) {
    new Main().run();
  }

  private void run() {
    try (
            InputReader in = new InputReader(System.in);
            PrintWriter out = new PrintWriter(System.out)) {
      solve(in, out);
    }
  }


  static class InputReader implements AutoCloseable {
    private BufferedReader reader;
    private StringTokenizer tokenizer;

    public InputReader(InputStream stream) {
      reader = new BufferedReader(new InputStreamReader(stream), 32768);
      tokenizer = null;
    }

    public String next() {
      while (tokenizer == null || !tokenizer.hasMoreTokens()) {
        try {
          tokenizer = new StringTokenizer(reader.readLine());
        } catch (IOException e) {
          throw new RuntimeException(e);
        }
      }
      return tokenizer.nextToken();
    }


    public int nextInt() {
      return Integer.parseInt(next());
    }

    public long nextLong() {
      return Long.parseLong(next());
    }

    public double nextDouble() {
      return Double.parseDouble(next());
    }

    @Override
    public void close() {

    }
  }

}