#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); i++)
#define rrep(i, n) for (int i = (n) - 1; i >= 0; i--)
#define reps(i, n) for (int i = 1; i <= (n); i++)
#define repi(i, a, b) for (int i = (a); i < (b); i++)
#define all(a) (a).begin(), (a).end()
#define bit(b) (1ll << (b))

using namespace std;
using i32 = int;
using u32 = unsigned int;
using i64 = long long;
using u64 = unsigned long long;
using f64 = double;
using f80 = long double;
using pii = pair<i32, i32>;
using vi32 = vector<i32>;
using vu32 = vector<u32>;
using vi64 = vector<i64>;
using vu64 = vector<u64>;
using vf64 = vector<f64>;
using vf80 = vector<f80>;
using vstr = vector<string>;
using vpii = vector<pii>;
using vvi32 = vector<vi32>;
using vvu32 = vector<vu32>;
using vvi64 = vector<vi64>;
using vvu64 = vector<vu64>;
using vvf64 = vector<vf64>;
using vvf80 = vector<vf80>;

template<typename T, typename S> bool amax(T &x, S y) { if (x < y) { x = y; return 1; } return 0; }
template<typename T, typename S> bool amin(T &x, S y) { if (y < x) { x = y; return 1; } return 0; }

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout << fixed << setprecision(16);
  cerr << fixed << setprecision(16);
  f80 r, d;
  cin >> r >> d;
  f80 a = sqrt(pow(d, 2) - pow(r, 2));
  cout << a << endl;
  return 0;
}