#include <bits/stdc++.h>
#pragma warning(disable : 6031)
#pragma warning(disable : 4101)
using namespace std;
const int INF = 1e9;
const long long LINF = 1e18;
const double PI = acos(-1);
long long h, l;
int main() {
  scanf("%lld%lld", &h, &l);
  printf("%lf\n", (l * l - h * h) / (2.0 * h));
  return 0;
}
