There are 5 red pens, 7 blue pens, and 6 yellow pens in the box. At least how many pens must be found to ensure that at least one is a red pen.
箱子里放着红笔5支，蓝笔7支，黄笔6支，至少要摸出多少支笔才能保证至少有1支是红笔．
<gadget id="calculator">7 + 6 + 1</gadget>
<output>14</output>

<result>14</result>