There are 8 blue balls, 6 red balls, and 3 yellow balls in black pockets. Touch the balls at will, at least how many balls you touch to ensure that you have all three colors.
有8个蓝色球，6个红色球，3个黄色球放入黑色口袋，任意摸球，至少摸多少个才能保证三色都有．
<gadget id="calculator">8 + 6 + 1</gadget>
<output>15</output>

<result>15</result>