#include <bits/stdc++.h>
using namespace std;
using mii = map<int, int>;
using mll = map<long long int, long long int>;
using pii = pair<int, int>;
using pll = pair<long long int, long long int>;
using vi = vector<int>;
using vll = vector<long long int>;
const int mod = 1000000007;
long long int desc(long long int x, long long int y) { return x > y; }
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  double h, l;
  cin >> h >> l;
  double ans = (pow(l, 2) - pow(h, 2)) / (2 * h);
  cout << setprecision(10) << ans << '\n';
  return 0;
}
