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[] args) {
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
		long ans = -100100100100L;
		for(long i = 0 ; i <= n ; i++) {
			if(i * i <= n) {
				ans = Math.max(ans, i * i);
			}
		}
		System.out.println(ans);
	}
}