#include <cmath>
#include <iostream>
#include <utility>

int main() {
    using namespace std;
    int a, b;
    cin >> a >> b;
    if (a == b) {
        cout << format("{:.20f}\n", sqrt(a * a * 2));
    } else {
        if (a < b) { swap(a, b); }
        cout << format("{:.20f}\n", sqrt(a * a - b * b));
    }
}