There are 10 balls of red, yellow, and white each, and each person chooses two of them at will. Then at least a few people need to choose the balls to ensure that there must be two or more balls of the same color. same?
有红、黄、白三种颜色的小球各10个，每个人从中任意选择两个，那么至少需要几个人选择小球，才能保证必有两人或两人以上选择的小球的颜色完全相同？
<gadget id="calculator">3 + 2 + 1</gadget>
<output>6</output>

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

<result>7</result>