import java.util.Calendar;
public class Test{
public static void main(String args[]) {

int counter = 0;
Calendar c = Calendar.getInstance();
for (int i = 1900; i<=2000; i++){
    for (int j = 1; j <=12; j++){
        c.set(i, j, 1);
int day_of_week = c.get(Calendar.DAY_OF_WEEK);
if(day_of_week==4){
    counter++;
}
}
}
System.out.println(counter);

}
}