From the four flowers of red, yellow, blue, and purple, at least how many flowers are taken out to ensure that there must be two flowers of the same color.
从红、黄、蓝、紫四种颜色各2枝的花中，至少取出多少枝花，才能保证必有两枝花是同色的．
<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<result>5</result>