[{"sectionTitle":"题目描述","type":"Text","text":"原题来自：BalticOI 2009\r\n\r\n给你一个字符串，它是由某个字符串不断自我连接形成的。但是这个字符串是不确定的，现在只想知道它的最短长度是多少。","subType":"markdown"},{"sectionTitle":"输入格式","type":"Text","text":"第一行给出字符串的长度 $L$，第二行给出一个字符串，全由小写字母组成。","subType":"markdown"},{"sectionTitle":"输出格式","type":"Text","text":"输出最短的长度。","subType":"markdown"},{"sectionTitle":"样例","type":"Sample","text":"对于样例，我们可以利用 abc 不断自我连接得到 abcabcabc，读入的 cabcabca 是它的子串。","subType":"markdown","payload":["8\ncabcabca","3"]},{"sectionTitle":"数据范围与提示","type":"Text","text":"对于全部数据，$1\\le L\\le 10^6$。","subType":"markdown"}]