There are three colored balls: white, red, and black. There are 10 white and red balls; 7 red and black balls; and 5 black and white balls. How many balls of one color are there at most?
有白、红、黑三种颜色的球，白球、红球合在一起共10个；红球、黑球合在一起共7个；黑球、白球合在一起共5个．最多一种颜色的球有多少个．
<gadget id="calculator">10 + 7 + 5</gadget>
<output>22</output>

<gadget id="calculator">22 / 2</gadget>
<output>11</output>

<gadget id="calculator">11 - 7</gadget>
<output>4</output>

<gadget id="calculator">10 - 4</gadget>
<output>6</output>

<result>6</result>