There are 10 red, yellow and blue marbles mixed together (the size and shape are the same), blindfolded, at least how many marbles can be touched to ensure that there must be 3 marbles of the same color.
有红、黄、蓝三种颜色的弹珠各10颗混在一起(大小、形状均相同)，蒙上眼睛，至少摸出多少颗才能保证一定有3颗颜色相同的弹珠．
<gadget id="calculator">2 * 3</gadget>
<output>6</output>

<gadget id="calculator">6 + 1</gadget>
<output>7</output>

<result>7</result>