{"problem":{"name":"ss","description":{"content":"We will call a string that can be obtained by concatenating two equal strings an _even_ string. For example, `xyzxyz` and `aaaaaa` are even, while `ababab` and `xyzxy` are not. You are given an even s","description_type":"Markdown"},"platform":"AtCoder","limit":{"time_limit":2000,"memory_limit":262144},"difficulty":"None","is_remote":true,"is_sync":true,"sync_url":null,"sign":"abc066_b"},"statements":[{"statement_type":"Markdown","content":"We will call a string that can be obtained by concatenating two equal strings an _even_ string. For example, `xyzxyz` and `aaaaaa` are even, while `ababab` and `xyzxy` are not.\nYou are given an even string $S$ consisting of lowercase English letters. Find the length of the longest even string that can be obtained by deleting one or more characters from the end of $S$. It is guaranteed that such a non-empty string exists for a given input.\n\n## Constraints\n\n*   $2 \\leq |S| \\leq 200$\n*   $S$ is an even string consisting of lowercase English letters.\n*   There exists a non-empty even string that can be obtained by deleting one or more characters from the end of $S$.\n\n## Input\n\nInput is given from Standard Input in the following format:\n\n$S$\n\n[samples]","is_translate":false,"language":"English"}],"meta":{"iden":"abc066_b","tags":[],"sample_group":[["abaababaab","6\n\n*   `abaababaab` itself is even, but we need to delete at least one character.\n*   `abaababaa` is not even.\n*   `abaababa` is not even.\n*   `abaabab` is not even.\n*   `abaaba` is even. Thus, we should print its length, $6$."],["xxxx","2\n\n*   `xxx` is not even.\n*   `xx` is even."],["abcabcabcabc","6\n\nThe longest even string that can be obtained is `abcabc`, whose length is $6$."],["akasakaakasakasakaakas","14\n\nThe longest even string that can be obtained is `akasakaakasaka`, whose length is $14$."]],"created_at":"2026-03-03 11:01:14"}}