Distribute 400 cards to several students, and everyone can get one, but no more than 11 cards. Try to prove that at least 7 students get the same number of cards.
将400张卡片分给若干个同学，每人都能分到，但都不超过11张，试证明：至少有7名同学分到的卡片的张数相同．
<result>7</result>