=IFERROR(INDEX($A$1:$A$14,MATCH(0,COUNTIF($C$1:C1,$A$1:$A$14),0)),"")

注意：C1要空置，从C2输入公式

参考：
https://blog.csdn.net/STR_Liang/article/details/105182654
https://zhuanlan.zhihu.com/p/55219017?utm_id=0