There are 3 red balls, 5 yellow balls, and 7 blue balls in a wooden box. In order to ensure that two of the balls taken out are of different colors, what is the minimum number of balls that must be taken out?
木箱里装有红色球3个，黄色球5个，蓝色球7个，为保证取出的球中有两个的颜色不相同，则最少要取出多少个球？
<gadget id="calculator">7 + 1</gadget>
<output>8</output>

<result>8</result>