#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e3 + 5;
int arr[100001];
int main() {
  double h, l;
  scanf("%lf %lf", &h, &l);
  double x = (pow(l, 2) - pow(h, 2)) / (2 * h);
  printf("%lf", x);
  return 0;
}
