Homework

AtCoder

IDabc163_b

Time2000ms

Memory256MB

Difficulty—

Takahashi has $N$ days of summer vacation. His teacher gave him $M$ summer assignments. It will take $A_i$ days for him to do the $i$\-th assignment. He cannot do multiple assignments on the same day, or hang out on a day he does an assignment. What is the maximum number of days Takahashi can hang out during the vacation if he finishes all the assignments during this vacation? If Takahashi cannot finish all the assignments during the vacation, print `-1` instead. ## Constraints * $1 \leq N \leq 10^6$ * $1 \leq M \leq 10^4$ * $1 \leq A_i \leq 10^4$ ## Input Input is given from Standard Input in the following format: $N$ $M$ $A_1$ $...$ $A_M$ [samples]

Samples

Input #1

41 2
5 6

Output #1

30

For example, he can do the first assignment on the first $5$ days, hang out on the next $30$ days, and do the second assignment on the last $6$ days of the vacation. In this way, he can safely spend $30$ days hanging out.

Input #2

10 2
5 6

Output #2

\-1

He cannot finish his assignments.

Input #3

11 2
5 6

Output #3

0

He can finish his assignments, but he will have no time to hang out.

Input #4

314 15
9 26 5 35 8 9 79 3 23 8 46 2 6 43 3

Output #4

API Response (JSON)

{
  "problem": {
    "name": "Homework",
    "description": {
      "content": "Takahashi has $N$ days of summer vacation. His teacher gave him $M$ summer assignments. It will take $A_i$ days for him to do the $i$\\-th assignment. He cannot do multiple assignments on the same day,",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "abc163_b"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "Takahashi has $N$ days of summer vacation.\nHis teacher gave him $M$ summer assignments. It will take $A_i$ days for him to do the $i$\\-th assignment.\nHe cannot do multiple assignments on the same day,...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

Full JSON Raw Segments