import java.util.*;

public class Main {
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        int happyDay=0;
        for(int month=1;month<=12;month++){
            if(month==2){
                for(int day=1;day<=28;day++){
                    int day_1=day/10;
                    int day_2=day%10;
                    if(month==day_1+day_2){
                        happyDay++;
                    }
                }
            }else if(month==4 || month==6 || month==9 || month==11){
                for(int day=1;day<=30;day++){
                    int day_1=day/10;
                    int day_2=day%10;
                    if(month==day_1+day_2){
                        happyDay++;
                    }
                }
            }else{
                for(int day=1;day<=31;day++){
                    int day_1=day/10;
                    int day_2=day%10;
                    if(month==day_1+day_2){
                        happyDay++;
                    }
                }
            }
                
        }
        System.out.println(happyDay);
    }
}