#include<iostream>
#include<math.h>
#include<string.h>
#include<vector>
#include<iomanip>
using namespace std;

int main(){
	double a,b;
	cin >> a >> b;
	double sum=0;
	double x=abs(max(a,b)-min(a,b))/2;
	
	for(double i=x;;i=i-0.000001){
		sum+=abs((i-x)*(i+x))*0.000001;
		if(i<=0)break;	
	} 
	cout << fixed << setprecision(5) << sum*2 << endl;
	return 0;
}