{"raw_statement":[{"iden":"problem statement","content":"Given is a string $S$. From this string, Takahashi will make a new string $T$ as follows.\n\n*   First, mark one or more characters in $S$. Here, no two marked characters should be adjacent.\n*   Next, delete all unmarked characters.\n*   Finally, let $T$ be the remaining string. Here, it is forbidden to change the order of the characters.\n\nHow many strings are there that can be obtained as $T$? Find the count modulo $(10^9 + 7)$."},{"iden":"constraints","content":"*   $S$ is a string of length between $1$ and $2 \\times 10^5$ (inclusive) consisting of lowercase English letters."},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$S$"},{"iden":"sample input 1","content":"abc"},{"iden":"sample output 1","content":"4\n\nThere are four strings that can be obtained as $T$: `a`, `b`, `c`, and `ac`.\nMarking the first character of $S$ yields `a`;\nmarking the second character of $S$ yields `b`;\nmarking the third character of $S$ yields `c`;\nmarking the first and third characters of $S$ yields `ac`.\nNote that it is forbidden to, for example, mark both the first and second characters."},{"iden":"sample input 2","content":"aa"},{"iden":"sample output 2","content":"1\n\nThere is just one string that can be obtained as $T$, which is `a`. Note that marking different positions may result in the same string."},{"iden":"sample input 3","content":"acba"},{"iden":"sample output 3","content":"6\n\nThere are six strings that can be obtained as $T$: `a`, `b`, `c`, `aa`, `ab`, and `ca`."},{"iden":"sample input 4","content":"chokudai"},{"iden":"sample output 4","content":"54"}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}