#include <bits/stdc++.h>
using namespace std;

int main()
{
    double a, b;
    cin >> a >> b;
    double l, s;
    if (a > b)
    {
        s = b;
        l = a;
    }
    else if (a < b)
    {
        s = a;
        l = b;
    }
    else
    {
        cout << sqrtf64(2) * a;
        return 0;
    }
    double ans = sqrtf64(pow(l, 2) - pow(s, 2));
    cout << setprecision(15) << ans;
}