#include <iostream>
#include <cstdlib>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <iomanip>

int main()
{
    int a, b;
    std::cin >> a >> b;
    double c;
    if(a == b){
        c = std::sqrt(2) * a;
    } else {
        c = a < b ? std::sqrt(b * b - a * a) : std::sqrt(a * a - b * b);
    }
    std::cout << std::fixed << std::setprecision(6) << c << std::endl;
    return 0;
}