There are 5 blue balls, 6 red balls, and 7 white balls of the same size in a cardboard box. How many times must you touch to ensure that you get 2 balls of the same color?
纸箱里有同样大小蓝球5个，红球6个，白球7个，要想确保摸出2个同色的球，至少要摸多少次
<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<result>4</result>