public class Answer {
	public static void main(String str[]) {

		int sum = 0;
		int maxDate;

		for(int i=1; i<=12; i++) {
			switch(i) {
			case 2:
				maxDate = 28;
				break;
			case 1:
			case 3:
			case 5:
			case 7:
			case 8:
			case 10:
			case 12:
				maxDate = 31;
				break;
			default:
				maxDate = 30;
			}
				for(int j=1; j<=maxDate; j++) {
					int ten = j/10;
					int one = j%10;
					if(i==(ten+one)) {
						sum++;
					}
				}
		}
        System.out.println(sum);
	}
}