Problem: While sailing on a boat, Inessa noticed a beautiful water lily flower above the lake's surface. She came closer and it turned out that the lily was exactly H centimeters above the water surface. Inessa grabbed the flower and sailed the distance of L centimeters. Exactly at this point the flower touched the water surface.

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Suppose that the lily grows at some point A on the lake bottom, and its stem is always a straight segment with one endpoint at point A. Also suppose that initially the flower was exactly above the point A, i.e. its stem was vertical. Can you determine the depth of the lake at point A?

Input

The only line contains two integers H and L (1 ≤ H < L ≤ 10^{6}).

Output

Print a single number — the depth of the lake at point A. The absolute or relative error should not exceed 10^{-6}.

Formally, let your answer be A, and the jury's answer be B. Your answer is accepted if and only if \frac{|A - B|}{max{(1, |B|)}} ≤ 10^{-6}.

Examples

Input


1 2


Output


1.5000000000000


Input


3 5


Output


2.6666666666667

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
template <typename T>
void OutN(T x) {
  size_t i, len = x.size() - 1;
  for (i = 0; i < len; i++) cout << x[i] << " ";
  cout << x[len] << '\n';
}
template <typename T>
void Outit(T x) {
  auto end = x.end();
  end--;
  for (auto it = x.begin(); it != end; it++) cout << *it << " ";
  cout << *end << '\n';
}
template <typename T>
void Debug(const T &val) {
  cerr << val << '\n';
}
template <typename T, typename... Args>
void Debug(const T &val, Args... args) {
  cerr << val << ' ';
  Debug(std::forward<Args>(args)...);
}
template <typename T>
inline bool Max(T &x, const T &y) {
  return x < y ? x = y, 1 : 0;
}
template <typename T>
inline bool Min(T &x, const T &y) {
  return x > y ? x = y, 1 : 0;
}
template <typename T>
using V = vector<T>;
template <typename T>
using VV = V<V<T> >;
static const long long MOD = 1e9 + 7;
static const double PI = 3.141592653589793;
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  std::cout.precision(18);
  double H, L;
  cin >> H >> L;
  double base = sqrt(H * H + L * L);
  double theta = atan(L / H);
  double deg = theta * (180.0 / PI);
  double topDeg = 180.0 - deg * 2.0;
  double halfTopDeg = topDeg / 2.0;
  double x = (base / 2.0) / sin(halfTopDeg * (PI / 180.0));
  cout << (x - H) << '\n';
  return 0;
}