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) {
		Scanner reader = new Scanner(System.in);
		int X = reader.nextInt();
		int ans = getMaxSquareBase(X);

		System.out.println((int)Math.pow(ans, 2));
		reader.close();
	}

	public static int getMaxSquareBase(int num) {
		int base = 1;
		while (Math.pow((base + 1), 2) <= num) {
			base++;
		}
		return base;
	}
}