#include <iostream>
#include <iomanip>
#include <cmath>

using ldouble = long double;

void solve() {
    ldouble r, d;
    std::cin >> r >> d;
    std::cout << std::fixed << std::setprecision(12)
              << std::sqrt(d * d - r * r) << std::endl;
}

int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    solve();

    return 0;
}