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.*;
import java.util.Scanner;

public class bai1060B {
	private static int dem(long n) {
		int d=0;
		long m=n;
		while(m>0) {
			d++;
			m/=10;
		}
		return d;
	}
	private static int tinh(long n) {
		int dem=0;
		long m=n;
		while(m>0) {
			dem+=m%10;
			m/=10;
		}
		return dem;
	}
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long n=sc.nextLong();
		long[] a= {9L, 99L, 999L, 9999L, 99999L, 999999L, 9999999L, 99999999L, 999999999L, 9999999999L, 99999999999L, 999999999999L};
		if(n<10) {
			System.out.print(n);
		}
		else {
			int x=dem(n);
			long y=n-a[x-2];
			int ans = tinh(y)+tinh(a[x-2]);
			System.out.print(ans);
		}
	}
}