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: Accepted)

#include <stdio.h>
#include <math.h>
 
int main()
{
    long num;
    int i;
    float fVar;
  
   
    scanf("%d",&num);
  for(i=num;i>=1;i--)
{
    
     int temp = i,count=1;
      while(temp > 0)
      {
            temp = temp - count;
            count = count + 2;
      }
      if(temp == 0)
      {
            printf("%d", i);
            break;
      }
      

 
    
 }  
    return 0;
}