Dango

AtCoder

IDabc299_c

Time2000ms

Memory256MB

Difficulty—

For a positive integer $L$, a level-$L$ dango string is a string that satisfies the following conditions. * It is a string of length $L+1$ consisting of `o` and `-`. * Exactly one of the first character and the last character is `-`, and the other $L$ characters are `o`. For instance, `ooo-` is a level-$3$ dango string, but none of `-ooo-`, `oo`, and `o-oo-` is a dango string (more precisely, none of them is a level-$L$ dango string for any positive integer $L$). You are given a string $S$ of length $N$ consisting of the two characters `o` and `-`. Find the greatest positive integer $X$ that satisfies the following condition. * There is a contiguous substring of $S$ that is a level-$X$ dango string. If there is no such integer, print `-1`. ## Constraints * $1\leq N\leq 2\times10^5$ * $S$ is a string of length $N$ consisting of `o` and `-`. ## Input The input is given from Standard Input in the following format: $N$ $S$ [samples]

Samples

Input #1

10
o-oooo---o

Output #1

4

For instance, the substring `oooo-` corresponding to the $3$\-rd through $7$\-th characters of $S$ is a level-$4$ dango string. No substring of $S$ is a level-$5$ dango string or above, so you should print $4$.

Input #2

1
-

Output #2

\-1

Only the empty string and `-` are the substrings of $S$. They are not dango strings, so you should print `-1`.

Input #3

30
-o-o-oooo-oo-o-ooooooo--oooo-o

Output #3

API Response (JSON)

{
  "problem": {
    "name": "Dango",
    "description": {
      "content": "For a positive integer $L$, a level-$L$ dango string is a string that satisfies the following conditions. *   It is a string of length $L+1$ consisting of `o` and `-`. *   Exactly one of the first ch",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "abc299_c"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "For a positive integer $L$, a level-$L$ dango string is a string that satisfies the following conditions.\n\n*   It is a string of length $L+1$ consisting of `o` and `-`.\n*   Exactly one of the first ch...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

Full JSON Raw Segments