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

using ldouble = long double;

void solve() {
    ldouble a, b;
    std::cin >> a >> b;

    ldouble c;
    if (a == b) {
        c = std::sqrt(2L) * a;
    } else {
        if (a > b) std::swap(a, b);
        c = std::sqrt(b * b - a * a);
    }

    std::cout << std::fixed << std::setprecision(10)
              << c << std::endl;
}

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

    solve();

    return 0;
}