Together Square

AtCoder

IDabc254_d

Time2000ms

Memory256MB

Difficulty—

You are given an integer $N$. Find the number of pairs $(i,j)$ of positive integers at most $N$ that satisfy the following condition: * $i \times j$ is a square number. ## Constraints * $1 \le N \le 2 \times 10^5$ * $N$ is an integer. ## Input Input is given from Standard Input in the following format: $N$ [samples]

Samples

Input #1

Output #1

6

The six pairs $(1,1),(1,4),(2,2),(3,3),(4,1),(4,4)$ satisfy the condition.
On the other hand, $(2,3)$ does not, since $2 \times 3 =6$ is not a square number.

Input #2

Output #2

API Response (JSON)

{
  "problem": {
    "name": "Together Square",
    "description": {
      "content": "You are given an integer $N$. Find the number of pairs $(i,j)$ of positive integers at most $N$ that satisfy the following condition: *   $i \\times j$ is a square number.",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "abc254_d"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "You are given an integer $N$. Find the number of pairs $(i,j)$ of positive integers at most $N$ that satisfy the following condition:\n\n*   $i \\times j$ is a square number.\n\n## Constraints\n\n*   $1 \\le ...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

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