String base = "1234567890qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVB";
Random random = new Random();
String st = new String();
for(int i = 0 ;i<10;i++){
do{
int number = random.nextInt(base.length());
st = st+base.charAt(number);
}while(list2.contains(st));
list2.add(st);
