import java.util.Scanner;

public class Main {

	static Scanner sc = new Scanner(System.in);

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