#define _GLIBCXX_DEBUG
#define ll long long
#include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;

int main(){
  int A, B; cin >> A >> B;
  if(A > B) swap(A, B);
  double ans = sqrt(B*B - A*A); 
  if(A == B) ans = sqrt(A*A + B*B);
  cout << setprecision(10) << ans << endl;
}