$$a_1$$,$$a_2$$,$$a_3$$,$$a_4$$, $$a_5$$,$$a_6$$ are six integers, which are not equal to each other. f(x)=-$$x^{2}$$. What is the least number of results that can be achieved by substituting $$a_1$$,$$a_2$$,$$a_3$$,$$a_4$$, $$a_5$$,$$a_6$$ into f(x)?
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正确答案: B