Problem:
Score : 200 points

Problem Statement

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.

Sample Input 1

10

Sample Output 1

9

10 is not square, but 9 = 3 × 3 is. Thus, we print 9.

Sample Input 2

81

Sample Output 2

81

Sample Input 3

271828182

Sample Output 3

271821169

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Runtime Error)

public class Main {

	public static void main(String[] args) {
		int x = Integer.parseInt(args[0]);
		int y = 0;
		double z = Math.sqrt(1000000000);
		for(int i=1; i<=z; i++){
			if(i*i<x){
				y = i*i;
			}else if( i*i ==x){
				System.out.println(x);
				y = -1;
				break;
			}else if(i*i > x){
				break;
			}
		}

		if( y != -1){
			System.out.println(y);
		}

	}

}