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>
 
int main(void)
{
    int n,a={0},max,i;
      
    scanf("%d",&n);
   
    max=0;
    for(i=0;i<n;i++){
        a=i*i;
        if(max<=a) max=a;
    }
  
    printf("%d\n",max);
    
    return 0;
}