#include <bits/stdc++.h>
using namespace std;
int main() {
  int h, l;
  scanf("%d %d", &h, &l);
  double x = double(h);
  double y = double(l);
  double res = (y * y - x * x) / x;
  res = res / (double)2;
  printf("%0.13f", res);
}
