There are 5 balls of red, yellow, and blue colors, and at least how many balls can be drawn to ensure that there are three colors.
有红、黄、蓝三种颜色的球各5个，至少摸出多少个才能保证有三种颜色．
<gadget id="calculator">5 * 2</gadget>
<output>10</output>

<gadget id="calculator">10 + 1</gadget>
<output>11</output>

<result>11</result>