#include <bits/stdc++.h>
using namespace std;
const int inf = 2e9;
const long long Inf = 1e10;
const int N = 500005;
const double pi = acos(-1);
inline int IN() {
  int x = 0;
  int ch = 0, f = 0;
  for (ch = getchar(); ch != -1 && (ch < 48 || ch > 57); ch = getchar())
    f = (ch == '-');
  for (; ch >= 48 && ch <= 57; ch = getchar())
    x = (x << 1) + (x << 3) + ch - '0';
  return f ? (-x) : x;
}
int Pow(int x, int y, int p) {
  int a = 1;
  for (; y; y >>= 1, x = (long long)x * x % p)
    if (y & 1) a = (long long)a * x % p;
  return a;
}
int n, a;
double rad[N], dis[N], ang[N];
struct po {
  double x, y;
  po(double xv = 0, double yv = 0) { x = xv, y = yv; }
  double norm() { return sqrt(x * x + y * y); }
  po operator-(const po &a) const { return (po){x - a.x, y - a.y}; }
} b[N], P, Q;
pair<double, double> A[N];
int tot;
set<double> st;
int check(double rng) {
  tot = 0;
  st.clear();
  for (int i = (int)(1); i <= (int)(n); i++) {
    if (dis[i] >= rng + rad[i]) continue;
    if (dis[i] <= fabs(rng - rad[i])) continue;
    double bet =
        (rng * rng + dis[i] * dis[i] - rad[i] * rad[i]) / (2 * rng * dis[i]);
    double alp = ang[i];
    bet = acos(bet);
    double l = alp - bet, r = alp + bet;
    if (l < 0) l += 2 * pi;
    if (r < 0) r += 2 * pi;
    if (l > r) swap(l, r);
    A[++tot] = make_pair(l, r);
  }
  sort(A + 1, A + tot + 1);
  for (int i = (int)(1); i <= (int)(tot); i++) {
    auto t = st.lower_bound(A[i].first);
    if (t != st.end() && *t < A[i].second) return 1;
    st.insert(A[i].second);
  }
  return 0;
}
int main() {
  scanf("%d%d", &n, &a);
  P = po(a, 0);
  Q = po(-a, 0);
  for (int i = (int)(1); i <= (int)(n); i++) {
    double x, y;
    scanf("%lf%lf", &x, &y);
    b[i] = po(x, y);
    rad[i] = (b[i] - Q).norm();
    b[i] = b[i] - P;
    ang[i] = atan2(b[i].y, b[i].x);
    dis[i] = b[i].norm();
  }
  double l = 0, r = 2 * a;
  for (int i = (int)(1); i <= (int)(100); i++) {
    double md = (l + r) / 2.;
    if (check(md))
      r = md;
    else
      l = md;
  }
  printf("%.10lf\n", (l + r) / 2);
  return 0;
}
