A number of beads of three colors, red, white, and black, are placed in a pocket, and the minimum number of beads that can be found in the dark can ensure that there is a pair of beads of the same color.
有红、白、黑3种颜色的珠子各若干个，放在一个口袋里，在黑暗中最少摸出多少个就能保证有一对是同样颜色的珠子．
<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<result>4</result>