#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll inf = 1e9 + 7;
const double PI = 3.141592653589793;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  ll h, l, a, b;
  cin >> h >> l;
  a = (l * l) - (h * h);
  b = 2 * h;
  double ans = (a * 1.0) / b;
  printf("%.7f\n", ans);
  return 0;
}
