题目描述
One day, Daizhenyang is wandering in BUPT campus, thinking about having a girlfriend. Out of nowhere, a breath-taking beautiful girl came by, Daizhenyang was shocked by her beauty and was too stunned to say hi.
There's an old saying, "Once there was true love for me but I did not cherish it. When it slipped away between my fingers, I began to regret. That is the saddest thing in life. If God could give me a second chance, I would tell the girl 'I love you!'. If there should be a time limit on this love, I wish it would be 10000 years." Regretting is what Daizhengyang is being through. He wants to make everything right, so he figured out her mail address and decides to send a love letter.
After thinking again and again for a long time, Daizhenyang picked up some keywords to express his love and emotion. However, Daizhenyang is busy on his eternal lasting enterprise, unifying all kinds of ACM/ICPC problems to network flow, he wants to make this letter as short as possible. You can help him on this holy project, making his dream come true.
输入描述:
There are multiple cases in the input file.
For each test case:
Line 1: an single integer N ( 0<N<=12 ) , represents the number of keywords.
Line 2 - N+1: a keyword in each line, keywords only consist of uppercase letters ( for sincerity ) , length is less than 56.
输出描述:
For each test case, output one line, begin with "Case #k: ", k is the case number, followed by the letter required. If there're several solutions output the lexicographically smaller one.
输入例子:
3
BUPT
TALENT
DAIZHENYANG
3
LOVE
VERY
RYTHM
输出例子:
Case #1: BUPTALENTDAIZHENYANG
Case #2: LOVERYTHM