public class Main {
    public static void main (String[] args) {
        
       int day ;
       int ans = 0;
        for (int i = 1; i <=12 ; i++){
            if(i == 2){
            day = 28 ;
            }else if (i==4|| i==6 || i==9 || i==11) {
            day = 30 ;
            }else{
            day = 31;    
            }
            
        for (int j =0 ; j <= day ; j++){
            if(i == (j/10) + (j%10)){
                ans += 1;
            }
        }
        }
        System.out.println(ans);
        
    }
}