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: Wrong Answer)

import java.util.*;

class Main{
  public static void main(String[] args)throws Exception{
    Scanner sc = new Scanner(System.in);
    
    int n = sc.nextInt();
    double ans = 0;
    
    for(int i=n; i>0; i++){
      ans = Math.sqrt(i);
      if((ans-(int)Math.sqrt(i))==0){
        break;
      }
    }
    
    System.out.println(ans+1);
  }
}