#include <bits/stdc++.h>
int main() {
  int L, H;
  long long Lsquare, Hsquare;
  long double depth;
  scanf("%d %d", &H, &L);
  Lsquare = (long long)L * (long long)L;
  Hsquare = (long long)H * (long long)H;
  depth = ((long double)Lsquare - (long double)Hsquare) / (2 * (long double)H);
  printf("%.6llf\n", depth);
  return 0;
}
