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;

/**
 * https://beta.atcoder.jp/contests/abc077/tasks/abc077_b
 */
public class Main {

	public static void main(String[] args) {
		
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		sc.close();
		
		int ans = 1;
		while((ans+1)*(ans+1)<=N){
			ans++;
		}
		System.out.println(ans*ans);

	}

}
