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:
//package com.example.hackerranksolutions;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.*;

public class Temp {



    public static void main (String[] args) throws Exception{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String s = br.readLine();
        Long n = Long.parseLong(s);
        StringBuilder sb = new StringBuilder();
        sb.append((char)(s.charAt(0)-1));
        for(int i = 1; i<s.length(); i++) sb.append('9');
        Long k = Long.parseLong(sb.toString());
        long sum = 0;
        for(int i = 0; i<sb.length(); i++) sum += sb.charAt(i)-'0';
        k = n-k;
        do {
            long x = k%10;
            k/=10;
            sum+=x;
        }while(k != 0);
        System.out.println(sum);
    }

}