#include <bits/stdc++.h>
using namespace std;
inline int read() {
  int ok = 1, k = 0;
  char c = getchar();
  while (c < '0' || c > '9') {
    if (c == '-') ok = -1;
    c = getchar();
  }
  while (c >= '0' && c <= '9') {
    k = k * 10 + c - '0';
    c = getchar();
  }
  return ok * k;
}
int main() {
  double h, l;
  scanf("%lf %lf", &h, &l);
  double ans = (h * h + l * l) / (2.0 * h);
  printf("%lf\n", ans - h);
  return 0;
}
