import java.util.ArrayDeque;
import java.util.Deque;

public class PenyimpanMemori<T> implements Penyimpan<T> {
    private final Deque<T> isi = new ArrayDeque<>();

    @Override
    public void simpan(T nilai) {
        isi.addLast(nilai);
    }

    @Override
    public T ambil() {
        return isi.pollLast();
    }

    @Override
    public int jumlah() {
        return isi.size();
    }
}