Case #1: abcd Case #2: abacac Case #3: IMPOSSIBLE Case #4: IMPOSSIBLE Case #5: abcd Case #6: ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff Case #7: afafafafbfcfdfeffbfbfcfdffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff Case #8: abaccfcccdeefffeffffbbfccbbfbedaffbefcdcfafcfe Case #9: IMPOSSIBLE Case #10: debbafdfacdfeccedfaddfaacfdadeeffeeceabccbdfdabafbceefbabeadffffeabaaebccebbdb Case #11: IMPOSSIBLE Case #12: ececbdbabcdadfecaaeaaecdcfacbdabbfbebdaecdcb Case #13: IMPOSSIBLE Case #14: aecbfaabfbddbaddcadcdcedbcebecefebddbbefbacffaebdacbfaaafbeabbcbaccbbcefddeefbcbceec Case #15: IMPOSSIBLE Case #16: cadebfbecfbdebfcabcbbfbfceadafeecedadec Case #17: IMPOSSIBLE Case #18: ddcbaaacaddadcdbdbebfcaeadaffbecdfcfecfbc Case #19: afeedbfcaabfeababddffddcfbfbdcaeeecf Case #20: aaadfacfefdffdbbefcaccebcccadfeccbbecbbdbecaadfacffaebeacddedcaddbceacdeeffffacdacedcdfbdee Case #21: IMPOSSIBLE Case #22: bcbcbabcacdefebdeaafeecebaebbebbfbadafefaabbccafd Case #23: IMPOSSIBLE Case #24: afffebaafdbebeadfbacadfbfecbefddbacdbaefeddb Case #25: IMPOSSIBLE Case #26: adedfedbddeeacbbfbaadfbfbadfcadbeacffdabd Case #27: IMPOSSIBLE Case #28: dbffabaaabefbccaeddaaefabcbfcefeeefefdababecafecababafaee Case #29: IMPOSSIBLE Case #30: ebfefbbbbedafccbfbcfcdededaaeb Case #31: cbbfbfabfebaafabefabbeddeccfccaabdeccbbfddadfec Case #32: beeefdacdfeacfbdfceecbfdfcbddbbeadfedbdabfecfccabbccedfeebffaadcfeadadcfbcbeeeaf Case #33: IMPOSSIBLE Case #34: addecbcafdfabaffacacfbfcdcaefaffbefefbaafceadedbfefebe Case #35: IMPOSSIBLE Case #36: affbefadfbeafbccdfbbafbdcbaaddadebadabbeaaaeeaeaddaccb Case #37: IMPOSSIBLE Case #38: bafdabecbaacaccaceadaafacdceeaceeebcefcadcaeecba Case #39: IMPOSSIBLE Case #40: afbbfaeadbdecbabeedaaebefeafcebadeddddbaebdebbaceaacdaebfdcbdcfcbaaecaccccffdefaebdeaabfccacfacfeabe Case #41: IMPOSSIBLE Case #42: aaccbceaadddcdeaeafbcfcbddfbbadabfaeaadeeeaeebbaacadeeaeeecfdfafcaedbbffceebabbebedcaeebffdadedbdffb Case #43: cdefaabdaaaaebcfbddefaecdaceeafced Case #44: ffbacbbc Case #45: IMPOSSIBLE Case #46: bbbdcfabbacbcbfcddfcbfbcfbdbaeabadcdddefeffbefdfedddfffcfddfdfdaaeaeaafbdcefedbbaeee Case #47: IMPOSSIBLE Case #48: ccdbdcefeffbfbaebbaffbecceffdaeacded Case #49: IMPOSSIBLE Case #50: eaacceefdefdacfebbbeeedd Case #51: IMPOSSIBLE Case #52: daacfdcdcafaffcbffdcacabdcaacffdbcaadaccbdcfacadadecdcdeecabedddacecabeabadecdceecfebdcafcadbddbbd Case #53: IMPOSSIBLE Case #54: cfbaafcaabdaafaeafffeabbdfdddcbeadba Case #55: IMPOSSIBLE Case #56: ecbfaebfebedbbbdeafacdcdfadeddfacadaafccedbeadebddabeadabdccafcdfbdacacbfabc Case #57: IMPOSSIBLE Case #58: daabacaacfabeebadaadaadaefabdaaecafaaeaebadbdbdeedbffa Case #59: aabcfedcaaffafacadaaaaadaacefaeafaccfadbaaddaabfbdbdbbabcaabbecdebdfbdcceaaecbbdfcafbc Case #60: addaaaeaaaaaaaadfadeaadaafeaaaaecdbabaafdbccaaacdbadbe Case #61: aeaeaaaacbbbfcaaadadcaacadabecbbaccaedfaafdbfafddfcd Case #62: aadebacdbeaacddededbdafbccaeaaccaffcecbabafaddafdeacda Case #63: IMPOSSIBLE Case #64: adfadadadabeadeabaebaeaacabbceacbadacfccbbeafadcdfcafefcdaeafbbadedaaaceeefaecefabbaddeaafafafda Case #65: aaaaaaebacbaaaeadaaeabdceaeaabcaafabadfaeddaaffccfecafffcfefcdecdbbdfadddeedfabeaeec Case #66: adbecbbeeabdaaeefbfefaafefcbceaaaaaadaaa Case #67: adeabdaddaaaacabeadafbdcbcfdedebaacbcceefadcefebbfbe Case #68: aadbdffecbdaadaaaaaaeaadaaaaddaaeafcaebdaabcadfaacafa Case #69: IMPOSSIBLE Case #70: afaeaaaaaacaaaaaeadacbaaaebdedafccaeccaaaffafdfbeefbdfbde Case #71: IMPOSSIBLE Case #72: aadaeacabcaacaaaaafcacabadadefcebdfa Case #73: IMPOSSIBLE Case #74: adadaeaacafecbdaafaadaacaa Case #75: IMPOSSIBLE Case #76: aaeaaaeaaaabcaafcf Case #77: dedcacafccfaedcbaabfaeecbaadfe Case #78: babaeaacaaaaaabeaaaaaaeecaacecccdedfffeef Case #79: aecacbcabcbafddbdabfaadfebedfaea Case #80: baaadceaaaaacabaacbaadbcfffaaaaaabfbadcbacadbceadbafaeafcfdadacfeadaedfcde Case #81: IMPOSSIBLE Case #82: daadaaadacafdabacaaaaacabbbddf Case #83: badacadcaadadfedcddafbadaaadfaefdcdcceadaeedc Case #84: ccaaaaaaacdcdecccaaafcaaaaddabcadaebeaaaaaaaaacaaadabaaaaaaaaacfabfedbaaaaafcafbceeeeeaddbbbaafd Case #85: IMPOSSIBLE Case #86: abaafeaacfafaaaabddae Case #87: fcadacdadbbcaededffaaf Case #88: eafaaaabaaaabaaaeaeaaaaaaaaafaaaaaafaacaaaafafaaffaaaaaaafaafbeceabaaaaacaebadebbadbbaadbaaaebbdbeaa Case #89: facfaabeadaaecabaaaaaffaacacafcaeadaababaefa Case #90: aaabadaaaaaaaaaaaaaaaaaaaaaaaeaaadabaaabcfadaaae Case #91: afeaaacfaaaaaaeabaaeaaabadaaaaefcbbaaeadabaaeaaafbddadcaffbeaeaaafcabafeaeeabcccafcfb Case #92: aaaaaaaaacaaabdaaaaaaaaaaaaabaaacadaaaacfafdbaaaaaafafaaacfeaabaafaaaaaadafb Case #93: adfaaaaaaaefacaabcaaaacdaaaaeacaaeffaaaaddadaaaaaabebbbbcfbeabcdfbda Case #94: aaacaacaaaeaaaaaaadabfd Case #95: addaaaaaaaebacaacaaaaaaaabacfcfeadaf Case #96: aaaaaaaebaaaaaaaabadafafea Case #97: IMPOSSIBLE Case #98: ecaecdaafaccfdcaeacddeaedfdcffbbeffbedaeeaffaac Case #99: IMPOSSIBLE Case #100: fdfeefaaafeccbdddecefbfaaeccffcbbbbe Case #101: IMPOSSIBLE Case #102: ebdafbbcdbfcfabeadfadedcaeebcfbed Case #103: IMPOSSIBLE Case #104: dfecfcbfabbeaaefdddadfbecadaafadcfbcafbefbabcbfebbfddbfaabfeecdfdbaccadbdbacdebcceaaccdb Case #105: IMPOSSIBLE Case #106: eeafbebdeebbcccefedfbaceadbfabaf Case #107: IMPOSSIBLE