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 sc = new Scanner(System.in);
      	//数値の入力
		long n = sc.nextLong();
      	long count = 0;
      	
        for(long i = 1; i <= n; i++){
        	if(i*i<=n){
              count++;
            }
        }
              System.out.println(count*count);
     }
}