uva10789測資A

Input:

20
ABCC
AABBBBDDDDD
ABCDFFFF
BCAC
ADBDDBABDBD
BDBDBADDBDA
BDBDBADDBDAEEEEE
FBDBEEEDBADDBDAEEF
AABBabba
10223782327absasAABBCDDD
1282sasAAB3921299972
ADCBDDKJLXKSJKDSLBABDBDEFHSGDKS
ADCHSGGDSHH3KJLXKSJKDSLBABDBDEFHSDJBDD238834HSGDKS
ADCKJLXKSJKDSDBDEFHSGGDSHHHSDJBDDXKSJKDSLBGDKSHS
ADCKJDEFHJBDDXKSJKDsdfsdfs992333BSGDKSHSGGDSHHHSDJ23423SLBDDXKSJKDSLB
ADCKJLXKSJKDSLBKDSLfs9SLBABDABEEBABBDAdDABDBDEFHSGDEDBADDBDAEEKSHSGGDSHHHSDJBDDXKSJKDSLB92ELBKD
ADCKJLXKSEDBADDBdfLBKDSLBAs992ELBKDSLBDAEEJKDSBDABDBDEFHSGDKJSJSJSSHSGGDSHHHSDJBDDXKSJKDSLB
SLBDAdfs992ELBKDSLBAsAasAAB39BDABEEB88343KJLXKSJ327absa212SLBABfs99233DABD
SGGDSHHHSDJBDD2388343KJLXKSJKDSLBAsdkllkksdkkkDSDBDEFHSGDlsdflaldfsdfsdfowe09dfjlaskdjfsldflsdfadgfdBDBDEFHSGDKSADCKJLXKSJKKSHSGGDSHHHSDJ
BK3afjHSDJBDDXKSAKSALaslDSLBDAdfs992ELBKDSLBABlsf9328492asfj3alfkksdfafjsalfwEEBABDABDBDEFHSGDEDBADDBDAEEKSHSGGDDABsdflksdjfl393SHHSDJKSMLXMXSK

Output:

Case 1: C
Case 2: AD
Case 3: empty
Case 4: C
Case 5: AD
Case 6: AD
Case 7: ADE
Case 8: ADEF
Case 9: ABab
Case 10: 37ABDas
Case 11: 12As
Case 12: ADJL
Case 13: 38AGHJLS
Case 14: BGHLX
Case 15: 239DGHJLXdfs
Case 16: 9DEGHSX
Case 17: 9ABDEGHJX
Case 18: 289DEJKLafs
Case 19: 38ABEFLXajk
Case 20: 239BDEGHJKLMXk