What is wrong with mycode? it is working in mycomputer but failing in test2

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;
/**
 * Created by sherxon on 3/17/14.
 */
public class Biathlon {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n=Integer.parseInt(in.nextLine());
        String s, name, time;
        Double min, sec;
        int j=0;
        List<String> a= new ArrayList();
        ArrayList<Double> b= new ArrayList();
        int thirty=0;

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

               s = in.nextLine();


            name=s.split(" ")[0];

            sec=Double.parseDouble(s.split(" ")[1].split(":")[1])+60*(Double.parseDouble(s.split(" ")[1].split(":")[0]));
               sec+=thirty;
               //System.out.println(sec);
               double eachsec=0.0;
               double eachsecs=0.0;
                boolean bl=true;


               for (int k = 0; k<a.size() ; k++) {
                 //  System.out.println(sec-thirty + " " + (b.get(k)-eachsec) + " " +(sec) + " " + b.get(k));


                   if(sec-thirty<b.get(k)-eachsec&&sec<b.get(k)){
                       b.remove(k);
                       a.remove(k);
                       k--;
                   }
                   eachsec+=30;
               }
               for (int k = 0; k <a.size() ; k++) {
                   if(sec-thirty>b.get(k)-eachsecs){
                       bl=false;
                   }
                   eachsecs+=30;
               }
                if(bl){
               a.add(name);
               b.add(sec);
                }

               thirty+=30;
        }
        Collections.sort(a);
        System.out.println(a.size());

        for (int i = 0; i <a.size() ; i++) {
            System.out.println(a.get(i));
        }
    }
}