1.ABCD 2.ABCE 3.ABE 4.BC 5.ABE 6.ACE 7.ABC
8.ABD 9.ABE 10.ADE 11.ABC 12.ACDE 13.ACE 14.ABC(https://www.daowen.com)
15.CDE 16.ACDE 17.BC 18.ABC 19.ABCD 20.CDE 21.ABE
