Wang Lan has 3 shirts and 3 skirts of different colors. How many days can she guarantee that the clothes she wears every day are not exactly the same.
王兰有3件不同颜色的衬衫和3件不同颜色的裙子．她最多能在多少天内保证每天穿的服装不完全一样．
<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<result>9</result>