#include <bits/stdc++.h>
using namespace std;
long long arr[26001];
void print(vector<int> v) {
  vector<int>::iterator it = v.begin();
  while (it != v.end()) {
    cout << *it << " ";
    it++;
  }
  cout << endl;
}
long long hcf(long long n, long long m) {
  if (m == 0) return n;
  if (n < m) swap(n, m);
  return hcf(m, n % m);
}
int rem(int x, int n) {
  if (x < 0) {
    if (x % n == 0)
      return 0;
    else
      return (x % n) + n;
  } else {
    return x % n;
  }
}
int main() {
  double h, l;
  cin >> h >> l;
  double ans = ((l * l - h * h) / 2) / h;
  cout << fixed << setprecision(7) << ans << endl;
}
