Definition: x〇y=x**2+y**2-x*y, then what is the value of (6○7)○(8○9).
定义：x〇y=x**2+y**2-x*y，那么(6○7)○(8○9)的值是多少．
<gadget id="calculator">6 ** 2</gadget>
<output>36</output>

<gadget id="calculator">7 ** 2</gadget>
<output>49</output>

<gadget id="calculator">6 * 7</gadget>
<output>42</output>

<gadget id="calculator">49 - 42</gadget>
<output>7</output>

<gadget id="calculator">36 + 7</gadget>
<output>43</output>

<gadget id="calculator">43 ** 2</gadget>
<output>1_849</output>

<gadget id="calculator">8 ** 2</gadget>
<output>64</output>

<gadget id="calculator">9 ** 2</gadget>
<output>81</output>

<gadget id="calculator">8 * 9</gadget>
<output>72</output>

<gadget id="calculator">81 - 72</gadget>
<output>9</output>

<gadget id="calculator">64 + 9</gadget>
<output>73</output>

<gadget id="calculator">73 ** 2</gadget>
<output>5_329</output>

<gadget id="calculator">43 * 73</gadget>
<output>3_139</output>

<gadget id="calculator">5_329 - 3_139</gadget>
<output>2_190</output>

<gadget id="calculator">1_849 + 2_190</gadget>
<output>4_039</output>

<result>4_039</result>