#include <iostream>
#include <vector>
#include <algorithm>
#include <map>
#include <queue>
#include <cstdio>
#include <ctime>
#include <assert.h>
#include <chrono>
#include <random>
#include <numeric>
#include <set>
using namespace std;
typedef long long int ll;
using ull = unsigned long long;



int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    double r,d; cin >> r >> d;
    printf("%.9f\n",sqrt(d*d-r*r));
}