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class LRUCache extends LinkedHashMap<Integer, Integer> {

    private int capacity;

    public LRUCache(int capacity) {
        super(capacity, 1, true);
        this.capacity = capacity;
    }

    @Override
    protected boolean removeEldestEntry(Map.Entry eldest) {
        return size() > capacity;
    }

    public int get(int key) {
        return format(super.get(key));
    }

    private int format(Integer value) {
        if (value == null) {
            return -1;
        }
        return value;
    }
}