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: Runtime Error)

#include<stdio.h>
#include<math.h>
int main()
{
	int n;
	double m,c;
	while(~scanf("%d",n))
	{
		m = n;
		c = sqrt(m);
		if(pow(c,2)==m)
		{
			printf("%d",n);
		}
		else 
		{
			printf("%d",pow(c,2));
		}
	}
	return 0;
}