public class Main {

	public static void main(String[] args) {
		
		int endmonth[] = {31,28,31,30,31,30,31,31,30,31,30,31};
		int count = 0;
		
		for(int i = 1 ; i <= 12 ; i++){
			for(int j = 1 ; j <= endmonth[i-1] ; j++){
				int day = 0;
				int tenday = j/10;
				if (tenday != 0){
					day = j-(tenday*10);
				}else{
					day = j;
				}
				if(day+tenday ==i){
					count++;
				}
			}
		}
		
		System.out.println(count);

	}

}