Some students move a pile of bricks. If each person moves X pieces, there will be 20 pieces left. If each person moves 9 pieces, the last student will only move 6 pieces. How many students are there in total?
一些学生搬一堆砖，若每人搬X块，则剩下20块，若每人搬9块，则最后一名学生只搬6块，那么学生共有多少人．
<result>23</result>