import java.util.*;
import java.lang.*;
import java.io.*;


class Main
{
	public static void main (String[] args) throws java.lang.Exception
	{
	int count = 0;
		// your code goes here
		for(int i=1;i<=12;i++){
			for(int day = 1;day<=30;day++){
				if(i == day%10 + day/10)
				count += 1;
			}
		}
		System.out.println(count);
	}
}