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.Date;
import java.util.Scanner;

public class Main2 {
    private static int[] ai;
    private static long[] helperResult;
    public static void main(String[] args) {
        long inputNum = new Scanner(System.in).nextLong();
        long n1 = 0;
        int firstNum;
        int sum1 = 0;
        int sum2= 0;
        long n2 = 0;
        int length = (int) (Math.log10(inputNum)+1);
        firstNum = (int) (inputNum / Math.pow(10,length-1));
        n1 = (long) (firstNum * Math.pow(10,length-1))-1;
        n2 = inputNum - n1;
        System.out.println(getDigitsSum(n1) + getDigitsSum(n2));
//        System.out.println(n1 + "   " + n2);
    }
    private static int getDigitsSum(long number){
        int result = 0;
        while (number > 0){
            result = (int) (result +( number %10));
            number = number/10;
        }
        return result;
    }

}