Dentist Aoki

AtCoder

IDabc350_b

Time2000ms

Memory256MB

Difficulty—

Takahashi has $N$ teeth, one in each of the holes numbered $1, 2, \dots, N$. Dentist Aoki will perform $Q$ treatments on these teeth and holes. In the $i$\-th treatment, hole $T_i$ is treated as follows: * If there is a tooth in hole $T_i$, remove the tooth from hole $T_i$. * If there is no tooth in hole $T_i$ (i.e., the hole is empty), grow a tooth in hole $T_i$. After all treatments are completed, how many teeth does Takahashi have? ## Constraints * All input values are integers. * $1 \le N, Q \le 1000$ * $1 \le T_i \le N$ ## Input The input is given from Standard Input in the following format: $N$ $Q$ $T_1$ $T_2$ $\dots$ $T_Q$ [samples]

Samples

Input #1

30 6
2 9 18 27 18 9

Output #1

28

Initially, Takahashi has $30$ teeth, and Aoki performs six treatments.

*   In the first treatment, hole $2$ is treated. There is a tooth in hole $2$, so it is removed.
*   In the second treatment, hole $9$ is treated. There is a tooth in hole $9$, so it is removed.
*   In the third treatment, hole $18$ is treated. There is a tooth in hole $18$, so it is removed.
*   In the fourth treatment, hole $27$ is treated. There is a tooth in hole $27$, so it is removed.
*   In the fifth treatment, hole $18$ is treated. There is no tooth in hole $18$, so a tooth is grown.
*   In the sixth treatment, hole $9$ is treated. There is no tooth in hole $9$, so a tooth is grown.

The final count of teeth is $28$.

Input #2

1 7
1 1 1 1 1 1 1

Output #2

Input #3

9 20
9 5 1 2 2 2 8 9 2 1 6 2 6 5 8 7 8 5 9 8

Output #3

API Response (JSON)

{
  "problem": {
    "name": "Dentist Aoki",
    "description": {
      "content": "Takahashi has $N$ teeth, one in each of the holes numbered $1, 2, \\dots, N$.   Dentist Aoki will perform $Q$ treatments on these teeth and holes.   In the $i$\\-th treatment, hole $T_i$ is treated as f",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "abc350_b"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "Takahashi has $N$ teeth, one in each of the holes numbered $1, 2, \\dots, N$.  \nDentist Aoki will perform $Q$ treatments on these teeth and holes.  \nIn the $i$\\-th treatment, hole $T_i$ is treated as f...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

Full JSON Raw Segments