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.*;
 
public class Main {
	public static void main (String[] args) {
		Scanner in = new Scanner(System.in);
		
		int n = in.nextInt();
      	long nam = 0;
      
      for(int i =1;i <= n ;i++){
        if(n>=i*i){nam=i*i;}
        else{break;}
      }
      System.out.print(nam);
	}
}