Achieve the Goal

AtCoder

IDabc151_b

Time2000ms

Memory256MB

Difficulty—

Takahashi is taking exams on $N$ subjects. The score on each subject will be an integer between $0$ and $K$ (inclusive). He has already taken exams on $N-1$ subjects and scored $A_i$ points on the $i$\-th subject. His goal is to achieve the average score of $M$ points or above on the $N$ subjects. Print the minimum number of points Takahashi needs on the final subject to achieve his goal. If the goal is unachievable, print `-1` instead. ## Constraints * $2 \leq N \leq 100$ * $1 \leq K \leq 100$ * $1 \leq M \leq K$ * $0 \leq A_i \leq K$ * All values in input are integers. ## Input Input is given from Standard Input in the following format: $N$ $K$ $M$ $A_1$ $A_2$ $...$ $A_{N-1}$ [samples]

Samples

Input #1

5 10 7
8 10 3 6

Output #1

8

If he scores $8$ points on the final subject, his average score will be $(8+10+3+6+8)/5 = 7$ points, which meets the goal.

Input #2

4 100 60
100 100 100

Output #2

0

Scoring $0$ points on the final subject still meets the goal.

Input #3

4 100 60
0 0 0

Output #3

\-1

He can no longer meet the goal.

API Response (JSON)

{
  "problem": {
    "name": "Achieve the Goal",
    "description": {
      "content": "Takahashi is taking exams on $N$ subjects. The score on each subject will be an integer between $0$ and $K$ (inclusive). He has already taken exams on $N-1$ subjects and scored $A_i$ points on the $i$",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "abc151_b"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "Takahashi is taking exams on $N$ subjects. The score on each subject will be an integer between $0$ and $K$ (inclusive).\nHe has already taken exams on $N-1$ subjects and scored $A_i$ points on the $i$...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

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