There are 4 white balls, 3 red balls and 2 yellow balls in a box, at least how many balls must be drawn to ensure that the drawn balls must have two colors of balls.
一个盒子里有4个白球、3个红球和2个黄球，至少摸出多少个球才能保证摸出的球一定有两种颜色的球．
<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<result>5</result>