#include <bits/stdc++.h>
int main() {
  unsigned long long int H, L;
  long double height;
  while (scanf("%lld %lld", &H, &L) != EOF) {
    height = (long double)((L * L) - (H * H)) / (long double)(2 * H);
    printf("%.13Lf\n", height);
  }
  return 0;
}
