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

int main()
{
    double a,b;
    std::cin >> a >> b;
    std::cout << std::fixed << std::setprecision(7) << std::sqrt(b * b - a * a) << std::endl;
    return 0;
}