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: Accepted)

import java.util.Scanner;

/**
 * Created by itounagamitsu on 2017/11/09.
 */
public class Main {

    public static void main(String[] args){
        Scanner scaner = new Scanner(System.in);

        int num = scaner.nextInt();

        for(int i=1;;i++){
            if(i * i > num){
                System.out.println((i-1) * (i-1));
                break;
            }
        }
    }
}