#include <bits/stdc++.h>
using namespace std;
inline long long read() {
  long long ret = 0, f = 0;
  char c = getchar();
  while (!isdigit(c)) {
    if (c == '-') f = 1;
    c = getchar();
  }
  while (isdigit(c)) {
    ret = ret * 10 + c - 48;
    c = getchar();
  }
  if (f) return -ret;
  return ret;
}
const long long N = 100005;
long long n, x, y, xu[N];
double A, B;
signed main() {
  cin >> B >> A;
  double x = (A * A - B * B) / (1.0 * B * 2.0);
  printf("%.10lf\n", x);
  return 0;
}
