There are several balls of 6 different colors in a box, how many balls should be taken at a time to ensure that at least 7 balls have the same color.
一个盒子里有6种颜色不同的小球若干个，一次最少取多少个才能保证其中至少有7个小球颜色相同．
<gadget id="calculator">6 * 6</gadget>
<output>36</output>

<gadget id="calculator">36 + 1</gadget>
<output>37</output>

<result>37</result>