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.

Examples

Input

10


Output

9


Input

81


Output

81


Input

271828182


Output

271821169
import java.util.Scanner;
public class Main {
public static void main(String[]srgs) {
	Scanner scan=new Scanner(System.in);
	int a=scan.nextInt();
	int ans=1;
	for(int i=a;i!=0;i--) {
		if(Math.sqrt(i)==(int)Math.sqrt(i)){
			System.out.println(i);
			break;
	}
	}
	scan.close();
}
}