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 C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>
#include <math.h>
 
int main()
{
    int num;
    int iVar,i;
    float fVar;
  
    printf("Enter an integer number: ");
    scanf("%d",&num);
num=abs(num);
  for(i=num;i<=0;i--)
{
    fVar=sqrt((double)i);
    iVar=fVar;

 
    if(iVar==fVar)
       {
        printf("%d ",i);
        break;
        }
 }  
    return 0;
}