class MyHashSet {

private static class LinkedList {

static class Node {

int val;

Node next;

public Node(int val) {

this.val = val;

}

}

private final Node dummy = new Node(0);

void add(int x) {

Node p = dummy.next;

while (p != null) {

if (p.val == x) break;

else p = p.next;

}

if (p == null) {

Node node = new Node(x);

node.next = dummy.next;

dummy.next = node;

}

}

void remove(int x) {

Node p = dummy;

while (p.next != null) {

if (p.next.val == x) {

p.next = p.next.next;

return;

}

p = p.next;

}

}

boolean contains(int x) {

Node p = dummy.next;

while(p != null) {

if(p.val == x) return true;

p = p.next;

}

return false;

}

}

private final LinkedList[] data;

private final static int N = 10;

/**

* Initialize your data structure here.

*/

public MyHashSet() {

data = new LinkedList[N];

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

data[i] = new LinkedList();

}

}

public void add(int key) {

int ind = key % N;

data[ind].add(key);

}

public void remove(int key) {

int ind = key % N;

data[ind].remove(key);

}

/**

* Returns true if this set contains the specified element

*/

public boolean contains(int key) {

int ind = key % N;

return data[ind].contains(key);

}

}

/**

* Your MyHashSet object will be instantiated and called as such:

* MyHashSet obj = new MyHashSet();

* obj.add(key);

* obj.remove(key);

* boolean param_3 = obj.contains(key);

*/