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 Java7 (OpenJDK 1.7.0) (judge verdict: Accepted)


import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
	// write your code here
        Scanner sc = new Scanner(System.in);
        long a= sc.nextLong();
        double k = Math.sqrt(a);
        long r = (long)k;
        if(k-r==0)
        {
            System.out.println(a);
        }
        else
        {
            long p =a-1;
            while(true)
            {
                k=Math.sqrt(p--);
                r=(long)k;
                if(k-r==0)
                {
                    System.out.println(p+1);
                    return;
                }
            }
        }


    }
}