Problem:
Score : 200 points

Problem Statement

Find the largest square number not exceeding N. Here, a square number is an integer that can be represented as the square of an integer.

Constraints

1 \leq N \leq 10^9

N is an integer.

Input

Input is given from Standard Input in the following format:

N

Output

Print the largest square number not exceeding N.

Sample Input 1

10

Sample Output 1

9

10 is not square, but 9 = 3 × 3 is. Thus, we print 9.

Sample Input 2

81

Sample Output 2

81

Sample Input 3

271828182

Sample Output 3

271821169

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		Main myself = new Main();
		int answer = myself.execute();

		System.out.print(answer);
	}

	/**
	 * 実処理メソッド
	 */
	public int execute() {

		try (Scanner scanner = new Scanner(System.in)) {

			final int N = scanner.nextInt();

			double sqrt = Math.sqrt(N);

			// iはテスト数
			for (int i = N; 0 < i; i--) {

				for (int j = (int) sqrt + 1; 0 < j; j--) {

					if (j * j == i) {
						return i;
					}
				}
			}

			return 0;
		}

	}

}