Call the ID Number

AtCoder

IDabc293_b

Time2000ms

Memory256MB

Difficulty—

There are $N$ people whose IDs are $1$, $2$, $\ldots$, and $N$. Each of person $1$, person $2$, $\ldots$, and person $N$ performs the following action once in this order: * If person $i$'s ID has not been called out yet, call out person $A_i$'s ID. Enumerate the IDs of all the people whose IDs are never called out until the end **in ascending order**. ## Constraints * $2 \leq N \leq 2 \times 10^5$ * $1 \leq A_i \leq N$ * $A_i \neq i$ * All values in the input are integers. ## Input The input is given from Standard Input in the following format: $N$ $A_1$ $A_2$ $\ldots$ $A_N$ [samples]

Samples

Input #1

5
3 1 4 5 4

Output #1

2
2 4

The five people's actions are as follows.

*   Person $1$'s ID has not been called out yet, so person $1$ calls out person $3$'s ID.
*   Person $2$'s ID has not been called out yet, so person $2$ calls out person $1$'s ID.
*   Person $3$'s ID has already been called out by person $1$, so nothing happens.
*   Person $4$'s ID has not been called out yet, so person $4$ calls out person $5$'s ID.
*   Person $5$'s ID has already been called out by person $4$, so nothing happens.

Therefore, person $2$ and $4$'s IDs are not called out until the end.

Input #2

20
9 7 19 7 10 4 13 9 4 8 10 15 16 3 18 19 12 13 2 12

Output #2

10
1 2 5 6 8 11 14 17 18 20

API Response (JSON)

{
  "problem": {
    "name": "Call the ID Number",
    "description": {
      "content": "There are $N$ people whose IDs are $1$, $2$, $\\ldots$, and $N$. Each of person $1$, person $2$, $\\ldots$, and person $N$ performs the following action once in this order: *   If person $i$'s ID has n",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "abc293_b"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "There are $N$ people whose IDs are $1$, $2$, $\\ldots$, and $N$.\nEach of person $1$, person $2$, $\\ldots$, and person $N$ performs the following action once in this order:\n\n*   If person $i$'s ID has n...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

Full JSON Raw Segments