// No.419 直角三角形
// https://yukicoder.me/problems/no/419
//
#include <iostream>
#include <cmath>
#include <iomanip>
using namespace std;

double solve(double a, double b);


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

    double a, b;
    cin >> a >> b;
    double ans = solve(a, b);
    cout << fixed << setprecision(8) << ans << endl;
}

double solve(double a, double b) {
    double ans;
    if (a == b)
        ans = sqrt(a*a + b*b);
    else {
        if (b > a) {
            double t = a;
            a = b;
            b = t;
        }
        ans = sqrt(a*a - b*b);
    }
    return ans;
}