When running, below programme cannot reach the end of the main function..

I am new to JAVA, and cannot find its defections.. I need your help. Thanks.

import java.util.*;

class Schedule {

public String day;
private int startTime, endTime;

public Schedule(String input_day, int input_start, int input_end) {

    day = input_day;
    startTime = input_start;
    endTime = input_end;
}

/* clashWith: to check whether this schedule clash with a Schedule called otherSchedule
 *      PRE-Condition  : input must be of Schedule type
 *      POST-Condition : return true if two Schedule clash, return false if not.
 */
public boolean clashWith(Schedule otherSchedule) { 

    if(this.day != otherSchedule.day || this.endTime <= otherSchedule.startTime || this.startTime >= otherSchedule.endTime)
        return false;

    return true;
}

}

class Module {

String code;
Schedule lecture, tutorial, lab;

public Module(String input_code, Schedule input_lecture, Schedule input_tutorial, Schedule input_lab) {

    code = input_code;
    lecture = input_lecture;
    tutorial = input_tutorial;
    lab = input_lab;
}

/* count: to count number of classes(lecture, tutorial, and lab of only this Module) on day.
 *        For example: when day = "Monday", lecture is on Monday, tutorial is on Monday
 *        but lab is on Tuesday, then return 2. (lecture and tutorial are on Monday).
 *      PRE-Condition  :
 *      POST-Condition :
 */
public int count(String day) {

    int num = 0;

    if(lecture.day == day)
        num++;

    if(tutorial.day == day)
        num++;

    if(lab.day == day)
        num++;

    return num;
}

/* clashWith: to check whether this module clash with a Module called otherModule
 *      PRE-Condition  :
 *      POST-Condition :
 */
public boolean clashWith(Module otherModule) {

    if(lecture.clashWith(otherModule.lecture) || lecture.clashWith(otherModule.tutorial) || lecture.clashWith(otherModule.lab) )
        return true;

    if(tutorial.clashWith(otherModule.lecture) || tutorial.clashWith(otherModule.tutorial) || tutorial.clashWith(otherModule.lab))
        return true;

    if(lab.clashWith(otherModule.lecture) || lab.clashWith(otherModule.tutorial) || lab.clashWith(otherModule.lab))
        return true;

    return false;
}

}

class Timetable {

Vector<Module> listOfModule;

public Timetable() {

}

/* checkClash: to check whether otherModule clash with one of 
 *             the modules in our timetable list.
 *      PRE-Condition  :
 *      POST-Condition :
 */
public boolean checkClash(Module otherModule) {

    for(Module c: listOfModule)
        if(c.clashWith(otherModule))
            return true;

    return false;
}

/* add: to add a new module to the timetable list.
 *      PRE-Condition  :
 *      POST-Condition :
 */
public void add(Module module) {

    listOfModule.add(module);

}

/* count: to count number of classes on day.
 *      PRE-Condition  :
 *      POST-Condition :
 */
public int count(String day) {

    int count_day=0;

    for(Module c: listOfModule)
        count_day += c.count(day);

    return count_day;
}

}

public class Main {

public static void main(String[] args) {

    Scanner input = new Scanner(System.in);
    int num_operation;
    String code ;
    Timetable userTimetable = new Timetable();

    num_operation = input.nextInt();

    for(int i=0;i<num_operation;i++) {

        if(input.next() == "MODULE") {

            code = input.next();

            String day;
            int start, end;

            Schedule getLecSche = new Schedule(input.next(),input.nextInt(),input.nextInt());

            Schedule getTutSche = new Schedule(input.next(),input.nextInt(),input.nextInt());

            Schedule getLabSche = new Schedule(input.next(),input.nextInt(),input.nextInt());

            Module userModule = new Module(code, getLecSche, getTutSche, getLabSche);

System.out.println("Reached line 162");

            if(!userTimetable.checkClash(userModule)) {

                userTimetable.add(userModule);
                System.out.println("Added");
            }
            else
                System.out.println("Clashed");

        }
        else if(input.next() == "COUNT"){

            code = input.next();

            System.out.println(userTimetable.count(code));

        }
    }

}

}