#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);
    int a,b; cin >> a >> b;
    if(a>b)swap(a,b);
    if(a==b)printf("%.9f\n",sqrt(2)*a );
    else printf("%.9f\n",sqrt(b*b-a*a));
}