#include <iostream>
#include <string>
#include <cmath> 
#include <iomanip>
using namespace std;

int main() {
    double a, b;
    cin >> a >> b;
    if ( a==b ) {
        cout << setprecision(9) <<  (double)sqrt(2) * (double)a;
    } else {
        cout << setprecision(9) << sqrt(abs(pow(a,2) - pow(b, 2))) << endl;;
    }
}