#include <iostream>
#include<bits/stdc++.h>
#define ll long long
#define ull unsigned long long
#define pi  3.14159
using namespace std;


int main() {
   ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);

double  a,ab;
cin>>a>>ab;


long  double r = sqrt(a/pi);

long double x2= pow((4*r),2);

 double x= sqrt(x2/2);  cout<<x;

 /*double area = (1/2)*(1/2)*x*ab;

cout<<area;*/

/*long double x= (sqrt(8)*r)/2;

long double y = (1/2)*((1/2)*x*ab);
cout<<y;*/
return 0;
}