[{"sectionTitle":"题目描述","type":"Text","text":"原题来自：HNOI 2006\r\n\r\n给定 $n$ 个字符串 $S_1,S_2,\\cdots ,S_n$，要求找到一个最短的字符串 $T$，使得这 $n$ 个字符串都是 $T$ 的子串。","subType":"markdown"},{"sectionTitle":"输入格式","type":"Text","text":"第一行是一个正整数 $n$，表示给定的字符串的个数；\r\n\r\n以下的 $n$ 行，每行有一个全由大写字母组成的字符串。","subType":"markdown"},{"sectionTitle":"输出格式","type":"Text","text":"只有一行，为找到的最短的字符串 $T$。\r\n\r\n在保证最短的前提下，如果有多个字符串都满足要求，那么必须输出按字典序排列的第一个。","subType":"markdown"},{"sectionTitle":"样例","type":"Sample","text":"","subType":"markdown","payload":["2\nABCD\nBCDABC","ABCDABC"]},{"sectionTitle":"数据范围与提示","type":"Text","text":"对于全部数据，$1\\le n\\le 12,1\\le |S_i|\\le 50$。","subType":"markdown"}]