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.

Examples

Input

10


Output

9


Input

81


Output

81


Input

271828182


Output

271821169
#include <stdio.h>
#include <math.h>

int main(){
int N;
scanf("%d",&N);
N=(int)sqrt(N);
printf("%d",N*N);
return 0;
}