uva12335測資A

Input:
13
ba 2
ab 2
yzx 4
yxz 4
tfrx 7
xskbu 34
yqzwcjemf 295146
lukyfqpwti 3260923
ojwgkvrnstupbqcifyeh 1824205649548810776
hkbpdrtloaygmxusvwnz 2391142346944001410
kwxiajmldvnusteoghqr 1783433521897373665
mfgqbtrdlsujiwepznco 2339011756370241631
a 1
Output:
Case 1: ab
Case 2: ba
Case 3: xyz
Case 4: zyx
Case 5: ftrx
Case 6: uxskb
Case 7: fmqczjeyw
Case 8: yfwqtipklu
Case 9: hsueycpkbiqgtforvwnj
Case 10: odmxysuzbtvpkarlgwnh
Case 11: idlsmgtueoxhwqkvajnr
Case 12: qjnpfdegszubticwrolm
Case 13: a