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.math.*;
import java.io.*;
import java.lang.*;

public class Main {
	public static void main(String[] args) {
        FastReader sc = new FastReader();
        long n = sc.nextLong();
        if(n<=9)
        {
            System.out.println(n);
        }
        else
        {
            //I can always have length of n -1 9's;
            String s = Long.toString(n);
            int first = (s.charAt(0))-'0';
            first=first-1;
            int nines = s.length()-1;
            String s1="";
            s1=s1+first;
            //System.out.println(nines);
            //System.out.println(first);
            long sum = 9*nines;
            sum=sum+first;
            //System.out.println(sum);
            for(int i=0;i<nines;i++)
            {
                s1=s1+"9";
            }
            long num1=Long.parseLong(s1);
            long num2=n-num1;
            //System.out.println(num2);
            String s2=Long.toString(num2);
            for(char ch: s2.toCharArray())
            {
                sum=sum+(ch-'0');
            }
            System.out.println(sum);
            
        }
        	
    }
    public static int partition(int arr[], int low, int high) 
    { 
        int pivot = arr[high];  
        int i = (low-1);
        for (int j=low; j<high; j++) 
        { 
            if (arr[j] < pivot) 
            { 
                i++; 
                int temp = arr[i]; 
                arr[i] = arr[j]; 
                arr[j] = temp; 
            } 
        } 
        int temp = arr[i+1]; 
        arr[i+1] = arr[high]; 
        arr[high] = temp; 
  
        return i+1; 
    } 
    public static void sort(int arr[], int low, int high) 
    { 
        if (low < high) 
        { 
            int pi = partition(arr, low, high); 
            sort(arr, low, pi-1); 
            sort(arr, pi+1, high); 
        } 
    } 
    static class Pair
    {
        int x;
        int y;
        public Pair(int x, int  y)
        {
            this.x=x;
            this.y=y;
        }
    }
static class Comp implements Comparator<Pair>
    {
        public int compare(Pair p1, Pair p2)
        {
            return p1.y-p2.y;
        }
    }
    
    
    
    
    
    static int gcd(int a,int b)
    {
        if(b==0) return a;
        return gcd(b,a%b);
    }
    
    
    static void sort(int[] a) {
		ArrayList<Integer> l=new ArrayList<>();
		for (int i:a) l.add(i);
		Collections.sort(l);
		for (int i=0; i<a.length; i++) a[i]=l.get(i);
	}
    static void sort(long[] a) {
		ArrayList<Long> l=new ArrayList<>();
		for (long i:a) l.add(i);
		Collections.sort(l);
		for (int i=0; i<a.length; i++) a[i]=l.get(i);
	}
	static class FastReader {
		BufferedReader br;
		StringTokenizer st;
 
		public FastReader() {
			br = new BufferedReader(new InputStreamReader(System.in));
		}
 
		String next() {
			while (st == null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (final IOException e) {
					e.printStackTrace();
				}
			}
			return st.nextToken();
		}

		int nextInt() {
			return Integer.parseInt(next());
		}

		long nextLong() {
			return Long.parseLong(next());
		}

		double nextDouble() {
			return Double.parseDouble(next());
		}

		String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (final IOException e) {
				e.printStackTrace();
			}
			return str;
		}

		int[] nextIntArray(final int n) {
			final int a[] = new int[n];
			for (int i = 0; i < n; i++) {
				a[i] = Integer.parseInt(next());
			}
			return a;
		}

	}	
}


//Templates for Comparator and Classes - @jagrit_07
/*
Arrays.sort(newEmployees, new Comparator<Employee>() {
    @Override
    public int compare(Employee emp1, Employee emp2) {
        return emp1.getName().compareTo(emp2.getName());
    }
});
class Pair
	{
		
		long i; //index;
		long l; //left;
		long c; //cost;
		public Pair(long x,long y,long z)
		{
			this.i=x;
			this.l=y;
			this.c=z;
		}
		public String toString()
		{
			return this.i+" "+this.l+" "+this.c;
		}
	}
class Comp implements Comparator<Pair>
	{
		public int compare(Pair p1, Pair p2)
		{
			if(p1.c!=p2.c)
			{
				return (int)(p1.c-p2.c); //sort acc to cost;
			}
			else{
				return (int)(p1.i-p2.i); //sort acc to index;
			}
			
		}
	}
*/

/*
  HashMap - Put template - d.put(a1,d.getOrDefault(a1,0)+1);
  for (Map.Entry<String, Integer> entry : map.entrySet()) {
        System.out.println(entry.getKey() + ":" + entry.getValue());
    }
*/