There are 7 black, white, and red beads of the same size and shape in the bag. At least how many beads must be taken out of the bag to ensure that beads of the same color are taken out.
袋子里有黑色、白色、红色且大小形状一样的珠子各7个，至少要从袋子里取出多少个珠子才能保证取出同颜色的珠子．
<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<result>4</result>