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>

int main (void){
    long long i = 1,a,ans = 1;


    scanf("%lld",&a);

    
   while(i*i <= a){
       if(i*i > ans){
           ans = i*i;
       }
       i++;
   }
   printf("%lld\n",ans);
   
    return 0;
}