#include <stdio.h>
using namespace std;

double squre_root(double S,int times){
 double x1;
 double x0=S/2;
 while(times>0){
 x1=(x0+S/x0)/2;
 x0=x1;
 times--;
}
printf("%f",x1);
}
int main()
{
double s = 400;
int t = 10;
squre_root(s,t);
}