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 Java7 (OpenJDK 1.7.0) (judge verdict: Accepted)

import java.util.Scanner;

import javax.sql.rowset.serial.SerialArray;

public class Main {

		public static void main(String[] args){
			
			Scanner sc = new Scanner(System.in);

			int N = sc.nextInt();

			double k;
			for (int i = N ; i >  0. ; i--){
				k=Math.sqrt(i);
				if (Math.round(k) == k){
				    System.out.println(i);
					return;
				}
			}
		}
}