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.Arrays;
import java.util.Scanner;



public class principal {
	
	static long posix(double n, long pos){
		return (long)((n%Math.pow(10,pos ))/(Math.pow(10, pos-1)));
	}
	
	static long numero(double n){
		return (long)Math.log10(n)+1;
	}
	
	static long S(long n){
		long result=0;
		long limit=numero(n);
		for(long i=1;i<=limit;i++){
			result+=posix(n,i);
		}
		return result;
	}
	public static void main(String[] args) {
		
		
		Scanner sc = new Scanner(System.in);
		long n=(long)sc.nextDouble();
		
		long maior=(long) (posix(n,numero(n))*Math.pow(10, numero(n)-1)-1);
		long menor=(long)n-maior;
		
		System.out.print(S(maior)+S(menor));
		
	}
	
	
}