public static void main(String[] args){
if (args==null || args[0].length()<1){
System.out.println("parameter error");
} else {
int num=Integer.parseInt(args[0]);
if(10<=num && num<=20){
JunglePartyExtra party=new JunglePartyExtra(num);
} else{
System.out.println("error");
}
}
}