Draw a number from 3, 9, 15, 21, 27, so that none of the remaining 4 numbers is equal to the sum of the other 3 numbers, and the sum of no two numbers is equal to the sum of the other two numbers, then What is the number drawn.
从3、9、15、21、27中抽出一个数，使剩下的4个数，没有一个等于其它3个数的和，而且没有两个数的和与另两个数的和相等，那么抽出的这个数是多少．
<result>9</result>