import java.io.PrintWriter;
import java.util.*;

public class No0188 {
    public static void main(String[] args) {

        PrintWriter out = new PrintWriter(System.out);

        int ans=0;
        for(int month = 1; month <=12 ; month++) {
            int eoMonth = calcEoMonth(month);
            for(int day = 0; day < eoMonth; day++) {
                if(month == (day/10) + (day%10)){
                    ans++;
                }
            }
        }

        out.println(ans);
        out.flush();
    }
    private static int calcEoMonth(int month){
        int ret=0;
        switch (month){
            case 1:
            case 3:
            case 5:
            case 7:
            case 8:
            case 10:
            case 12:
                ret = 31;
                break;
            case 4:
            case 6:
            case 9:
            case 11:
                ret = 30;
                break;
            default:
                ret = 28;
                break;
        }
        return ret;
    }
}