Time Gap

AtCoder

IDcf17_final_c

Time2000ms

Memory256MB

Difficulty—

In CODE FESTIVAL XXXX, there are $N+1$ participants from all over the world, including Takahashi. Takahashi checked and found that the _time gap_ (defined below) between the local times in his city and the $i$\-th person's city was $D_i$ hours. The time gap between two cities is defined as follows. For two cities A and B, if the local time in city B is $d$ o'clock at the moment when the local time in city A is $0$ o'clock, then the time gap between these two cities is defined to be $min(d,24-d)$ hours. Here, we are using $24$\-hour notation. That is, the local time in the $i$\-th person's city is either $d$ o'clock or $24-d$ o'clock at the moment when the local time in Takahashi's city is $0$ o'clock, for example. Then, for each pair of two people chosen from the $N+1$ people, he wrote out the time gap between their cities. Let the smallest time gap among them be $s$ hours. Find the maximum possible value of $s$. ## Constraints * $1 \leq N \leq 50$ * $0 \leq D_i \leq 12$ * All input values are integers. ## Input Input is given from Standard Input in the following format: $N$ $D_1$ $D_2$ $...$ $D_N$ [samples]

Samples

Input #1

3
7 12 8

Output #1

4

For example, consider the situation where it is $7$, $12$ and $16$ o'clock in each person's city at the moment when it is $0$ o'clock in Takahashi's city. In this case, the time gap between the second and third persons' cities is $4$ hours.

Input #2

2
11 11

Output #2

Input #3

1
0

Output #3

0

Note that Takahashi himself is also a participant.

API Response (JSON)

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    "name": "Time Gap",
    "description": {
      "content": "In CODE FESTIVAL XXXX, there are $N+1$ participants from all over the world, including Takahashi. Takahashi checked and found that the _time gap_ (defined below) between the local times in his city an",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "cf17_final_c"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "In CODE FESTIVAL XXXX, there are $N+1$ participants from all over the world, including Takahashi.\nTakahashi checked and found that the _time gap_ (defined below) between the local times in his city an...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

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