Not Found

AtCoder

IDabc071_b

Time2000ms

Memory256MB

Difficulty—

You are given a string $S$ consisting of lowercase English letters. Find the lexicographically (alphabetically) smallest lowercase English letter that does not occur in $S$. If every lowercase English letter occurs in $S$, print `None` instead. ## Constraints * $1 \leq |S| \leq 10^5$ ($|S|$ is the length of string $S$.) * $S$ consists of lowercase English letters. ## Input Input is given from Standard Input in the following format: $S$ [samples]

Samples

Input #1

atcoderregularcontest

Output #1

b

The string `atcoderregularcontest` contains `a`, but does not contain `b`.

Input #2

abcdefghijklmnopqrstuvwxyz

Output #2

None

This string contains every lowercase English letter.

Input #3

fajsonlslfepbjtsaayxbymeskptcumtwrmkkinjxnnucagfrg

Output #3

API Response (JSON)

{
  "problem": {
    "name": "Not Found",
    "description": {
      "content": "You are given a string $S$ consisting of lowercase English letters. Find the lexicographically (alphabetically) smallest lowercase English letter that does not occur in $S$. If every lowercase English",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "abc071_b"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "You are given a string $S$ consisting of lowercase English letters. Find the lexicographically (alphabetically) smallest lowercase English letter that does not occur in $S$. If every lowercase English...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

Full JSON Raw Segments