{"problem":{"name":"Strings of Impurity","description":{"content":"Given are two strings $s$ and $t$ consisting of lowercase English letters. Determine if there exists an integer $i$ satisfying the following condition, and find the minimum such $i$ if it exists. *  ","description_type":"Markdown"},"platform":"AtCoder","limit":{"time_limit":2000,"memory_limit":262144},"difficulty":"None","is_remote":true,"is_sync":true,"sync_url":null,"sign":"abc138_e"},"statements":[{"statement_type":"Markdown","content":"Given are two strings $s$ and $t$ consisting of lowercase English letters. Determine if there exists an integer $i$ satisfying the following condition, and find the minimum such $i$ if it exists.\n\n*   Let $s'$ be the concatenation of $10^{100}$ copies of $s$. $t$ is a subsequence of the string ${s'}_1{s'}_2\\ldots{s'}_i$ (the first $i$ characters in $s'$).\n\n## Constraints\n\n*   $1 \\leq |s| \\leq 10^5$\n*   $1 \\leq |t| \\leq 10^5$\n*   $s$ and $t$ consists of lowercase English letters.\n\n## Input\n\nInput is given from Standard Input in the following format:\n\n$s$\n$t$\n\n[samples]\n\n## Notes\n\n*   A subsequence of a string $a$ is a string obtained by deleting zero or more characters from $a$ and concatenating the remaining characters without changing the relative order. For example, the subsequences of `contest` include `net`, `c`, and `contest`.","is_translate":false,"language":"English"}],"meta":{"iden":"abc138_e","tags":[],"sample_group":[["contest\nson","10\n\n$t =$ `son` is a subsequence of the string `contestcon` (the first $10$ characters in $s' =$ `contestcontestcontest...`), so $i = 10$ satisfies the condition.\nOn the other hand, $t$ is not a subsequence of the string `contestco` (the first $9$ characters in $s'$), so $i = 9$ does not satisfy the condition.\nSimilarly, any integer less than $9$ does not satisfy the condition, either. Thus, the minimum integer $i$ satisfying the condition is $10$."],["contest\nprogramming","\\-1\n\n$t =$ `programming` is not a substring of $s' =$ `contestcontestcontest...`. Thus, there is no integer $i$ satisfying the condition."],["contest\nsentence","33\n\nNote that the answer may not fit into a $32$\\-bit integer type, though we cannot put such a case here."]],"created_at":"2026-03-03 11:01:13"}}