The Organizing Committee of the "World Olympics" has 10 dolls each for Ao Zebra, Koizumi, Xiaomei, and Oou. The dolls are the same.
"世奥赛"组委会有奥斑马、小泉、小美、欧欧玩偶各10个，每个小朋友只能领走1个玩偶，至少要有多少个小朋友领玩偶，才能保证一定有3个小朋友领的玩偶是一样的．
<gadget id="calculator">4 + 4 + 1</gadget>
<output>9</output>

<result>9</result>