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.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.*;
import java.util.*;
import java.util.Map.Entry;

public class Main {

	public static void main(String[] args) throws IOException {
	    FastReader in = new FastReader(System.in);
		PrintWriter out = new PrintWriter(System.out);

		long n = in.nextLong();
		long a = 0;
		long t = 9;
		while (t * 10 + 9 < n) {
			t = t * 10 + 9;
		}
		a = n - t;
		out.println(sum(t) + sum(a));
		out.flush();
		out.close();

	}

	private static long sum(long a) {
		// TODO Auto-generated method stub
		if (a == 0) {
			return 0;
		} else {
			return sum(a / 10) + a % 10;
		}
	}

	static class FastReader {
		StringTokenizer st;
		BufferedReader br;

		public FastReader(InputStream s) {
			br = new BufferedReader(new InputStreamReader(s));
		}

		public FastReader(FileReader fileReader) {
			br = new BufferedReader(fileReader);
		}

		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

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

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

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

		public String nextLine() throws IOException {
			return br.readLine();
		}

		public boolean ready() throws IOException {
			return br.ready();
		}
	}

}