{"problem":{"name":"Leftrightarrow","description":{"content":"You are given a string $S$ consisting of `<`, `=`, and `>`.   Determine whether $S$ is a **bidirectional arrow** string.   A string $S$ is a bidirectional arrow string if and only if there is a positi","description_type":"Markdown"},"platform":"AtCoder","limit":{"time_limit":2000,"memory_limit":262144},"difficulty":"None","is_remote":true,"is_sync":true,"sync_url":null,"sign":"abc345_a"},"statements":[{"statement_type":"Markdown","content":"You are given a string $S$ consisting of `<`, `=`, and `>`.  \nDetermine whether $S$ is a **bidirectional arrow** string.  \nA string $S$ is a bidirectional arrow string if and only if there is a positive integer $k$ such that $S$ is a concatenation of one `<`, $k$ `=`s, and one `>`, in this order, with a length of $(k+2)$.\n\n## Constraints\n\n*   $S$ is a string of length between $3$ and $100$, inclusive, consisting of `<`, `=`, and `>`.\n\n## Input\n\nThe input is given from Standard Input in the following format:\n\n$S$\n\n[samples]","is_translate":false,"language":"English"}],"meta":{"iden":"abc345_a","tags":[],"sample_group":[["<====>","Yes\n\n`<====>` is a concatenation of one `<`, four `=`s, and one `>`, in this order, so it is a bidirectional arrow string.  \nHence, print `Yes`."],["\\==>","No\n\n`==>` does not meet the condition for a bidirectional arrow string.  \nHence, print `No`."],["<>>","No"]],"created_at":"2026-03-03 11:01:14"}}