#include <bits/stdc++.h>
using namespace std;
void solve() {
  double h, l, ans;
  cin >> h >> l;
  ans = (l * l - h * h) / h / 2;
  cout << fixed << setprecision(10) << ans << "\n";
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long t = 1;
  while (t--) {
    solve();
  }
  return 0;
}
