#include <stdio.h>
#include<math.h>
int main(void) {
	float a,x1,x2;
    scanf("%f",&a);
    x1=a/2;
    x2=(x1+a/x1)/2;
    while(fabs(x1-x2)>1e-5)
  {  x1=x2;
    x2=(x1+a/x1)/2;}
    printf("sqrt(a)= %f\n",x1);
	return 0;
}