#include <bits/stdc++.h>
using namespace std;
const int INF = 0x7fffffff;
const double Pi = acos(-1);
int main() {
  double H, L;
  scanf("%lf%lf", &H, &L);
  printf("%.10lf\n", (L * L - H * H) / (2 * H));
  return 0;
}
