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.*;
public class sadheart {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
		StringBuffer sb = new StringBuffer();
		sb.append(9);
		while(true){
			if(Long.parseLong(sb.toString())>n){
				break;
			}else{
				sb.append(9);
			}
		}
		String res = sb.toString().substring(1);
		String res2=""+n;
		long ans = 0;
		if(res.length()!=0){
		    ans = 9*res.length();
		    res2 = ""+(n-Long.parseLong(res));
		}
		 
		
		for(int i=0;i<res2.length();i++){
			ans+=res2.charAt(i)-'0';
		}
		System.out.println(ans);
		

	}

}