bag contains 12 beads of red, yellow, and black colors. At least how many beads are taken out of the bag to ensure that there are two beads of the same color.
一个袋子有红、黄、黑三种颜色的珠子各12个，至少从里面拿出多少个珠子，才能保证有两个珠子的颜色相同．
<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<result>4</result>