What is the value of simplification (19901991/(19901990**2-19901989*19901991)).
化简(19901991/(19901990**2-19901989*19901991))的值等于多少．
<gadget id="calculator">19_901_990 ** 2</gadget>
<output>396_089_205_960_100</output>

<gadget id="calculator">19_901_989 * 19_901_991</gadget>
<output>396_089_205_960_099</output>

<gadget id="calculator">396_089_205_960_100 - 396_089_205_960_099</gadget>
<output>1</output>

<gadget id="calculator">19_901_991 / 1</gadget>
<output>19_901_991</output>

<result>19_901_991</result>