#include <bits/stdc++.h>
using namespace std;
bool isSubSequence(string str1, string str2, int m, int n) {
  int j = 0;
  for (int i = 0; i < n && j < m; i++)
    if (str1[j] == str2[i]) j++;
  return (j == m);
}
int n, m, i, j, k;
int main() {
  float h, l;
  cin >> h >> l;
  float ans = l * l - h * h;
  ans /= 2;
  ans /= h;
  cout << fixed << setprecision(13) << ans << endl;
  return 0;
}
