// Slower C++ solution:
#include<bits/stdc++.h>



using namespace std;



const double EPS = 1e-10, PI = acos(-1);



inline bool eq(double a, double b) { return abs(b - a) < EPS; }



#define curr(P, i) P[i]

#define next(P, i) P[(i+1)%P.size()]

#define prev(P, i) P[(i+P.size()-1) % P.size()]

enum

{

  OUT, ON, IN

};

namespace Geometory

{

  struct Point

  {

    double x, y;



    Point() {};



    Point(double x, double y) : x(x), y(y) {};



    Point operator+(const Point &b) const { return Point(x + b.x, y + b.y); }



    Point operator-(const Point &b) const { return Point(x - b.x, y - b.y); }



    Point operator*(const double b) const { return Point(x * b, y * b); }



    Point operator*(const Point &b) const { return Point(x * b.x - y * b.y, x * b.y + y * b.x); }



    Point operator/(const double b) const { return Point(x / b, y / b); }



    bool operator<(const Point &b) const { return x != b.x ? x < b.x : y < b.y; }



    bool operator==(const Point &b) const { return eq(x, b.x) && eq(y, b.y); }



    double norm() { return x * x + y * y; }



    double arg() { return atan2(x, y); }



    double abs() { return sqrt(norm()); }



    Point rotate(double theta) { return Point(cos(theta) * x - sin(theta) * y, sin(theta) * x + cos(theta) * y); }



    Point rotate90() { return Point(-y, x); }



    friend ostream &operator<<(ostream &os, Point &p) { return os << "(" << p.x << "," << p.y << ")"; }



    friend istream &operator>>(istream &is, Point &a) { return is >> a.x >> a.y; }

  };



  struct Line

  {

    Point a, b;



    Line() {};



    Line(Point a, Point b) : a(a), b(b) {};



    friend ostream &operator<<(ostream &os, Line &p) { return os << "(" << p.a.x << "," << p.a.y << ") to (" << p.b.x << "," << p.b.y << ")"; }



    friend istream &operator>>(istream &is, Line &a) { return is >> a.a.x >> a.a.y >> a.b.x >> a.b.y; }

  };



  struct Segment

  {

    Point a, b;



    Segment() {};



    Segment(Point a, Point b) : a(a), b(b) {};



    friend ostream &operator<<(ostream &os, Segment &p) { return os << "(" << p.a.x << "," << p.a.y << ") to (" << p.b.x << "," << p.b.y << ")"; }



    friend istream &operator>>(istream &is, Segment &a) { return is >> a.a.x >> a.a.y >> a.b.x >> a.b.y; }

  };



  struct Circle

  {

    Point p;

    double r;



    Circle() {};



    Circle(Point p, double r) : p(p), r(r) {};

  };



  typedef vector< Point > Polygon;

  typedef vector< Segment > Segments;

  typedef vector< Line > Lines;

  typedef vector< Circle > Circles;

  typedef pair< Point, Point > PointPoint;



  double cross(const Point &a, const Point &b)

  {

    return a.x * b.y - a.y * b.x;

  }



  double dot(const Point &a, const Point &b)

  {

    return a.x * b.x + a.y * b.y;

  }



  int ccw(const Point &a, Point b, Point c)

  {

    b = b - a, c = c - a;

    if(cross(b, c) > EPS) return +1;  // a ??? b ?????§ ??????????¨??????????????????? c

    if(cross(b, c) < -EPS) return -1; // a ??? b ?????§ ???????¨??????????????????? c

    if(dot(b, c) < 0) return +2;  // c -- a -- b?????§????????´??????

    if(b.norm() < c.norm()) return -2; // a -- b -- c?????§????????´??????

    return 0;  // a -- c -- b?????§????????´??????

  }



  Point Projection(const Line &l, const Point &p)

  {

    double t = dot(p - l.a, l.a - l.b) / (l.a - l.b).norm();

    return l.a + (l.a - l.b) * t;

  }



  Point Projection(const Segment &l, const Point &p)

  {

    double t = dot(p - l.a, l.a - l.b) / (l.a - l.b).norm();

    return l.a + (l.a - l.b) * t;

  }



  Point Reflection(const Line &l, const Point &p)

  {

    return p + (Projection(l, p) - p) * 2.0;

  }



  double Distance(const Line &l, const Point &p)

  { //OK

    return (p - Projection(l, p)).abs();

  }



  bool Intersect(const Line &l, const Line &m)

  {

    return abs(cross(l.b - l.a, m.b - m.a)) > EPS || abs(cross(l.b - l.a, m.b - l.a)) < EPS;

  }



  bool Intersect(const Line &l, const Segment &s)

  {

    return cross(l.b - l.a, s.a - l.a) * cross(l.b - l.a, s.b - l.a) < EPS;

  }



  bool Intersect(const Line &l, const Point &p)

  {

    return abs(ccw(l.a, l.b, p)) != -1;

  }



  bool Intersect(const Segment &s, const Segment &t)

  {

    return ccw(s.a, s.b, t.a) * ccw(s.a, s.b, t.b) <= 0 && ccw(t.a, t.b, s.a) * ccw(t.a, t.b, s.b) <= 0;

  }



  bool Intersect(const Segment &s, const Point &p)

  {

    return ccw(s.a, s.b, p) == 0;

  }



  bool Intersect(const Circle &c, const Line &l)

  {

    return Distance(l, c.p) <= c.r + EPS;

  }



  bool Intersect(const Circle &c, const Point &p)

  {

    return abs((p - c.p).abs() - c.r) < EPS;

  }



  int Intersect(const Circle &c, const Segment &l)

  {

    if((Projection(l, c.p) - c.p).norm() - c.r * c.r > EPS) return 0;

    const double d1 = (c.p - l.a).abs(), d2 = (c.p - l.b).abs();

    if(d1 < c.r + EPS && d2 < c.r + EPS) return 0;

    if(d1 < c.r - EPS && d2 > c.r + EPS || d1 > c.r + EPS && d2 < c.r - EPS) return 1;

    const Point h = Projection(l, c.p);

    if(dot(l.a - h, l.b - h) < 0) return 2;

    return 0;

  }



  bool Intersect(const Circle &a, const Circle &b)

  {

    return ((a.p - b.p).norm() - (a.r + b.r) * (a.r + b.r) < EPS) &&

           ((a.p - b.p).norm() - (a.r - b.r) * (a.r - b.r) > -EPS);

  }



  double Distance(const Segment &s, const Point &p)

  {

    Point r = Projection(s, p);

    if(Intersect(s, r)) return (r - p).abs();

    return min((s.a - p).abs(), (s.b - p).abs());

  }



  double Distance(const Segment &a, const Segment &b)

  {

    if(Intersect(a, b)) return 0;

    return min(min(Distance(a, b.a), Distance(a, b.b)), min(Distance(b, a.a), Distance(b, a.b)));

  }



  double Distance(const Line &l, const Line &m)

  {

    return Intersect(l, m) ? 0 : Distance(l, m.a);

  }



  double Distance(const Line &l, const Segment &s)

  { //OK

    if(Intersect(l, s)) return 0;

    return min(Distance(l, s.a), Distance(l, s.b));

  }



  double Distance(const Point &a, const Point &b)

  { //OK

    return (a - b).abs();

  }



  Point Crosspoint(const Segment &l, const Segment &m)

  { //OK

    double A = cross(l.b - l.a, m.b - m.a);

    double B = cross(l.b - l.a, l.b - m.a);

    if(abs(A) < EPS && abs(B) < EPS) return m.a; // same line

    return m.a + (m.b - m.a) * B / A;

  }



  PointPoint Crosspoint(const Circle &c, const Line l)

  {

    Point hp = Projection(l, c.p), h = hp - c.p;

    const double d2 = h.norm();

    Point v = (l.b - l.a) * sqrt(c.r * c.r - d2) / (l.b - l.a).abs();

    return PointPoint(hp - v, hp + v);

  }



  PointPoint Crosspoint(const Circle &c, const Segment &l)

  {

    Line aa = Line(l.a, l.b);

    if(Intersect(c, l) == 2) return Crosspoint(c, aa);

    PointPoint ret = Crosspoint(c, aa);

    if(dot(l.a - ret.first, l.b - ret.first) < 0) ret.second = ret.first;

    else ret.first = ret.second;

    return ret;

  }



  PointPoint Crosspoint(const Circle &c1, const Circle &c2)

  { //OK

    double d = (c1.p - c2.p).abs();

    double s = (c1.r + c2.r + d) / 2;

    double S = sqrt(s * (s - c1.r) * (s - c2.r) * (s - d));

    double h = 2 * S / d;

    Point v = (c2.p - c1.p) / (c2.p - c1.p).abs();

    double m = sqrt(c1.r * c1.r - h * h);

    return PointPoint(c1.p + v * m + Point(0, 1) * h * v, c1.p + v * m - Point(0, 1) * h * v);

  }



  bool parallel(const Line &a, const Line &b)

  {

    return abs(cross(a.b - a.a, b.b - b.a)) < EPS;

  }



  bool orthogonal(const Line &a, const Line &b)

  {

    return abs(dot(a.a - a.b, b.a - b.b)) < EPS;

  }



  int Contains(const Polygon &Q, const Point &p)

  {

    bool in = false;

    for(int i = 0; i < Q.size(); i++) {

      Point a = curr(Q, i) - p, b = next(Q, i) - p;

      if(a.y > b.y) swap(a, b);

      if(a.y <= 0 && 0 < b.y && cross(a, b) < 0) in = !in;

      if(cross(a, b) == 0 && dot(a, b) <= 0) return ON;

    }

    return in ? IN : OUT;

  }



  bool Contains(const Circle &c, const Point &p)

  {

    return (c.p - p).abs() < c.r + EPS;

  }



  double Area2(const Polygon &p)

  { //OK

    double A = 0;

    for(int i = 0; i < p.size(); ++i) {

      A += cross(curr(p, i), next(p, i));

    }

    return A;

  }



  bool IsConvex(const Polygon &p)

  {

    for(int i = 0; i < p.size(); i++) {

      if(ccw(prev(p, i), curr(p, i), next(p, i)) == -1) return false;

    }

    return true;

  }



  Polygon Convex_Hull(Polygon &p)

  {

    int n = p.size(), k = 0;

    if(n >= 3) {

      sort(p.begin(), p.end());

      vector< Point > ch(2 * n);

      for(int i = 0; i < n; ch[k++] = p[i++]) {

        while(k >= 2 && cross(ch[k - 1] - ch[k - 2], p[i] - ch[k - 1]) < 0) --k;

      }

      for(int i = n - 2, t = k + 1; i >= 0; ch[k++] = p[i--]) {

        while(k >= t && cross(ch[k - 1] - ch[k - 2], p[i] - ch[k - 1]) < 0) --k;

      }

      ch.resize(k - 1);

      return ch;

    } else {

      return p;

    }

  }



  double Convex_Diameter(Polygon &p)

  {

    int n = p.size();

    int is = 0, js = 0;

    for(int i = 1; i < n; i++) {

      if(p[i].y > p[is].y) is = i;

      if(p[i].y < p[js].y) js = i;

    }

    double maxdis = (p[is] - p[js]).norm();



    int maxi, maxj, i, j;

    i = maxi = is;

    j = maxj = js;

    do {

      if(cross(next(p, i) - curr(p, i), next(p, j) - curr(p, j)) >= 0) {

        j = (j + 1) % n;

      } else {

        i = (i + 1) % n;

      }

      if((p[i] - p[j]).norm() > maxdis) {

        maxdis = (p[i] - p[j]).norm();

        maxi = i;

        maxj = j;

      }

    } while(i != is || j != js);

    return maxdis;

  }

};



using namespace Geometory;



int N, W;

int X[10], Y[10], H[10];



bool check(double r)

{

  auto getPadding = [&](double height)

  {

    if(r > height) return (r - sqrt(r * r - (r - height) * (r - height)));

    return (0.0);

  };



  vector< Circle > circles(N);

  for(int i = 0; i < N; i++) {

    circles[i].p = Point(X[i], Y[i]);

    circles[i].r = r - getPadding(H[i]);

  }

  double padding = r - getPadding(W);

  if(2 * padding >= 100) return (false);

  Polygon rectangle(4);

  rectangle[0] = Point(padding, padding);

  rectangle[1] = Point(100 - padding, padding);

  rectangle[2] = Point(100 - padding, 100 - padding);

  rectangle[3] = Point(padding, 100 - padding);



  vector< Point > crossed;

  for(int i = 0; i < N; i++) {

    for(int j = 0; j < i; j++) {

      if(Intersect(circles[i], circles[j])) {

        auto get = Crosspoint(circles[i], circles[j]);

        crossed.push_back(get.first);

        crossed.push_back(get.second);

      }

    }

  }

  for(int j = 0; j < N; j++) {

    for(int i = 0; i < 4; i++) {

      auto seg = Segment(curr(rectangle, i), next(rectangle, i));

      if(Intersect(circles[j], seg)) {

        auto get = Crosspoint(circles[j], seg);

        crossed.push_back(get.first);

        crossed.push_back(get.second);

      }

      crossed.push_back(rectangle[i]);

    }

  }



  for(auto &p : crossed) {

    bool isin = true;

    for(auto &c : circles) {

      isin &= (p - c.p).abs() + 1e-5 >= c.r;

    }

    isin &= Contains(rectangle, p) != OUT;

    if(isin) return (true);

  }

  return (false);

}



int main()

{

  while(scanf("%d %d", &N, &W), N) {

    for(int i = 0; i < N; i++) {

      scanf("%d %d %d", &X[i], &Y[i], &H[i]);

    }

    double low = 0, high = 200;

    for(int i = 0; i < 150; i++) {

      double mid = (low + high) * 0.5;

      if(check(mid)) low = mid;

      else high = mid;

    }

    printf("%.10lf\n", low);

  }

}

// Faster C++ solution for the same problem (measured speedup: 1.6609248060349835x):
#include<bits/stdc++.h>



using namespace std;



const double EPS = 1e-10, PI = acos(-1);



inline bool eq(double a, double b) { return abs(b - a) < EPS; }



#define curr(P, i) P[i]

#define next(P, i) P[(i+1)%P.size()]

#define prev(P, i) P[(i+P.size()-1) % P.size()]

enum

{

  OUT, ON, IN

};

namespace Geometory

{

  struct Point

  {

    double x, y;



    Point() {};



    Point(double x, double y) : x(x), y(y) {};



    Point operator+(const Point &b) const { return Point(x + b.x, y + b.y); }



    Point operator-(const Point &b) const { return Point(x - b.x, y - b.y); }



    Point operator*(const double b) const { return Point(x * b, y * b); }



    Point operator*(const Point &b) const { return Point(x * b.x - y * b.y, x * b.y + y * b.x); }



    Point operator/(const double b) const { return Point(x / b, y / b); }



    bool operator<(const Point &b) const { return x != b.x ? x < b.x : y < b.y; }



    bool operator==(const Point &b) const { return eq(x, b.x) && eq(y, b.y); }



    double norm() { return x * x + y * y; }



    double arg() { return atan2(x, y); }



    double abs() { return sqrt(norm()); }



    Point rotate(double theta) { return Point(cos(theta) * x - sin(theta) * y, sin(theta) * x + cos(theta) * y); }



    Point rotate90() { return Point(-y, x); }



    friend ostream &operator<<(ostream &os, Point &p) { return os << "(" << p.x << "," << p.y << ")"; }



    friend istream &operator>>(istream &is, Point &a) { return is >> a.x >> a.y; }

  };



  struct Line

  {

    Point a, b;



    Line() {};



    Line(Point a, Point b) : a(a), b(b) {};



    friend ostream &operator<<(ostream &os, Line &p) { return os << "(" << p.a.x << "," << p.a.y << ") to (" << p.b.x << "," << p.b.y << ")"; }



    friend istream &operator>>(istream &is, Line &a) { return is >> a.a.x >> a.a.y >> a.b.x >> a.b.y; }

  };



  struct Segment

  {

    Point a, b;



    Segment() {};



    Segment(Point a, Point b) : a(a), b(b) {};



    friend ostream &operator<<(ostream &os, Segment &p) { return os << "(" << p.a.x << "," << p.a.y << ") to (" << p.b.x << "," << p.b.y << ")"; }



    friend istream &operator>>(istream &is, Segment &a) { return is >> a.a.x >> a.a.y >> a.b.x >> a.b.y; }

  };



  struct Circle

  {

    Point p;

    double r;



    Circle() {};



    Circle(Point p, double r) : p(p), r(r) {};

  };



  typedef vector< Point > Polygon;

  typedef vector< Segment > Segments;

  typedef vector< Line > Lines;

  typedef vector< Circle > Circles;

  typedef pair< Point, Point > PointPoint;



  double cross(const Point &a, const Point &b)

  {

    return a.x * b.y - a.y * b.x;

  }



  double dot(const Point &a, const Point &b)

  {

    return a.x * b.x + a.y * b.y;

  }



  int ccw(const Point &a, Point b, Point c)

  {

    b = b - a, c = c - a;

    if(cross(b, c) > EPS) return +1;  // a ??? b ?????§ ??????????¨??????????????????? c

    if(cross(b, c) < -EPS) return -1; // a ??? b ?????§ ???????¨??????????????????? c

    if(dot(b, c) < 0) return +2;  // c -- a -- b?????§????????´??????

    if(b.norm() < c.norm()) return -2; // a -- b -- c?????§????????´??????

    return 0;  // a -- c -- b?????§????????´??????

  }



  Point Projection(const Line &l, const Point &p)

  {

    double t = dot(p - l.a, l.a - l.b) / (l.a - l.b).norm();

    return l.a + (l.a - l.b) * t;

  }



  Point Projection(const Segment &l, const Point &p)

  {

    double t = dot(p - l.a, l.a - l.b) / (l.a - l.b).norm();

    return l.a + (l.a - l.b) * t;

  }



  Point Reflection(const Line &l, const Point &p)

  {

    return p + (Projection(l, p) - p) * 2.0;

  }



  double Distance(const Line &l, const Point &p)

  { //OK

    return (p - Projection(l, p)).abs();

  }



  bool Intersect(const Line &l, const Line &m)

  {

    return abs(cross(l.b - l.a, m.b - m.a)) > EPS || abs(cross(l.b - l.a, m.b - l.a)) < EPS;

  }



  bool Intersect(const Line &l, const Segment &s)

  {

    return cross(l.b - l.a, s.a - l.a) * cross(l.b - l.a, s.b - l.a) < EPS;

  }



  bool Intersect(const Line &l, const Point &p)

  {

    return abs(ccw(l.a, l.b, p)) != -1;

  }



  bool Intersect(const Segment &s, const Segment &t)

  {

    return ccw(s.a, s.b, t.a) * ccw(s.a, s.b, t.b) <= 0 && ccw(t.a, t.b, s.a) * ccw(t.a, t.b, s.b) <= 0;

  }



  bool Intersect(const Segment &s, const Point &p)

  {

    return ccw(s.a, s.b, p) == 0;

  }



  bool Intersect(const Circle &c, const Line &l)

  {

    return Distance(l, c.p) <= c.r + EPS;

  }



  bool Intersect(const Circle &c, const Point &p)

  {

    return abs((p - c.p).abs() - c.r) < EPS;

  }



  int Intersect(const Circle &c, const Segment &l)

  {

    if((Projection(l, c.p) - c.p).norm() - c.r * c.r > EPS) return 0;

    const double d1 = (c.p - l.a).abs(), d2 = (c.p - l.b).abs();

    if(d1 < c.r + EPS && d2 < c.r + EPS) return 0;

    if(d1 < c.r - EPS && d2 > c.r + EPS || d1 > c.r + EPS && d2 < c.r - EPS) return 1;

    const Point h = Projection(l, c.p);

    if(dot(l.a - h, l.b - h) < 0) return 2;

    return 0;

  }



  bool Intersect(const Circle &a, const Circle &b)

  {

    return ((a.p - b.p).norm() - (a.r + b.r) * (a.r + b.r) < EPS) &&

           ((a.p - b.p).norm() - (a.r - b.r) * (a.r - b.r) > -EPS);

  }



  double Distance(const Segment &s, const Point &p)

  {

    Point r = Projection(s, p);

    if(Intersect(s, r)) return (r - p).abs();

    return min((s.a - p).abs(), (s.b - p).abs());

  }



  double Distance(const Segment &a, const Segment &b)

  {

    if(Intersect(a, b)) return 0;

    return min(min(Distance(a, b.a), Distance(a, b.b)), min(Distance(b, a.a), Distance(b, a.b)));

  }



  double Distance(const Line &l, const Line &m)

  {

    return Intersect(l, m) ? 0 : Distance(l, m.a);

  }



  double Distance(const Line &l, const Segment &s)

  { //OK

    if(Intersect(l, s)) return 0;

    return min(Distance(l, s.a), Distance(l, s.b));

  }



  double Distance(const Point &a, const Point &b)

  { //OK

    return (a - b).abs();

  }



  Point Crosspoint(const Segment &l, const Segment &m)

  { //OK

    double A = cross(l.b - l.a, m.b - m.a);

    double B = cross(l.b - l.a, l.b - m.a);

    if(abs(A) < EPS && abs(B) < EPS) return m.a; // same line

    return m.a + (m.b - m.a) * B / A;

  }



  PointPoint Crosspoint(const Circle &c, const Line l)

  {

    Point hp = Projection(l, c.p), h = hp - c.p;

    const double d2 = h.norm();

    Point v = (l.b - l.a) * sqrt(c.r * c.r - d2) / (l.b - l.a).abs();

    return PointPoint(hp - v, hp + v);

  }



  PointPoint Crosspoint(const Circle &c, const Segment &l)

  {

    Line aa = Line(l.a, l.b);

    if(Intersect(c, l) == 2) return Crosspoint(c, aa);

    PointPoint ret = Crosspoint(c, aa);

    if(dot(l.a - ret.first, l.b - ret.first) < 0) ret.second = ret.first;

    else ret.first = ret.second;

    return ret;

  }



  PointPoint Crosspoint(const Circle &c1, const Circle &c2)

  { //OK

    double d = (c1.p - c2.p).abs();

    double s = (c1.r + c2.r + d) / 2;

    double S = sqrt(s * (s - c1.r) * (s - c2.r) * (s - d));

    double h = 2 * S / d;

    Point v = (c2.p - c1.p) / (c2.p - c1.p).abs();

    double m = sqrt(c1.r * c1.r - h * h);

    return PointPoint(c1.p + v * m + Point(0, 1) * h * v, c1.p + v * m - Point(0, 1) * h * v);

  }



  bool parallel(const Line &a, const Line &b)

  {

    return abs(cross(a.b - a.a, b.b - b.a)) < EPS;

  }



  bool orthogonal(const Line &a, const Line &b)

  {

    return abs(dot(a.a - a.b, b.a - b.b)) < EPS;

  }



  int Contains(const Polygon &Q, const Point &p)

  {

    bool in = false;

    for(int i = 0; i < Q.size(); i++) {

      Point a = curr(Q, i) - p, b = next(Q, i) - p;

      if(a.y > b.y) swap(a, b);

      if(a.y <= 0 && 0 < b.y && cross(a, b) < 0) in = !in;

      if(cross(a, b) == 0 && dot(a, b) <= 0) return ON;

    }

    return in ? IN : OUT;

  }



  bool Contains(const Circle &c, const Point &p)

  {

    return (c.p - p).abs() < c.r + EPS;

  }



  double Area2(const Polygon &p)

  { //OK

    double A = 0;

    for(int i = 0; i < p.size(); ++i) {

      A += cross(curr(p, i), next(p, i));

    }

    return A;

  }



  bool IsConvex(const Polygon &p)

  {

    for(int i = 0; i < p.size(); i++) {

      if(ccw(prev(p, i), curr(p, i), next(p, i)) == -1) return false;

    }

    return true;

  }



  Polygon Convex_Hull(Polygon &p)

  {

    int n = p.size(), k = 0;

    if(n >= 3) {

      sort(p.begin(), p.end());

      vector< Point > ch(2 * n);

      for(int i = 0; i < n; ch[k++] = p[i++]) {

        while(k >= 2 && cross(ch[k - 1] - ch[k - 2], p[i] - ch[k - 1]) < 0) --k;

      }

      for(int i = n - 2, t = k + 1; i >= 0; ch[k++] = p[i--]) {

        while(k >= t && cross(ch[k - 1] - ch[k - 2], p[i] - ch[k - 1]) < 0) --k;

      }

      ch.resize(k - 1);

      return ch;

    } else {

      return p;

    }

  }



  double Convex_Diameter(Polygon &p)

  {

    int n = p.size();

    int is = 0, js = 0;

    for(int i = 1; i < n; i++) {

      if(p[i].y > p[is].y) is = i;

      if(p[i].y < p[js].y) js = i;

    }

    double maxdis = (p[is] - p[js]).norm();



    int maxi, maxj, i, j;

    i = maxi = is;

    j = maxj = js;

    do {

      if(cross(next(p, i) - curr(p, i), next(p, j) - curr(p, j)) >= 0) {

        j = (j + 1) % n;

      } else {

        i = (i + 1) % n;

      }

      if((p[i] - p[j]).norm() > maxdis) {

        maxdis = (p[i] - p[j]).norm();

        maxi = i;

        maxj = j;

      }

    } while(i != is || j != js);

    return maxdis;

  }

};



using namespace Geometory;



int N, W;

int X[10], Y[10], H[10];



bool check(double r)

{

  auto getPadding = [&](double height)

  {

    if(r > height) return (r - sqrt(r * r - (r - height) * (r - height)));

    return (0.0);

  };

  vector< Circle > circles(N);

  for(int i = 0; i < N; i++) {

    circles[i].p = Point(X[i], Y[i]);

    circles[i].r = r - getPadding(H[i]);

  }

  double padding = r - getPadding(W);

  if(2 * padding >= 100) return (false);

  Polygon rectangle(4);

  rectangle[0] = Point(padding, padding);

  rectangle[1] = Point(100 - padding, padding);

  rectangle[2] = Point(100 - padding, 100 - padding);

  rectangle[3] = Point(padding, 100 - padding);



  vector< Point > crossed;

  for(int i = 0; i < N; i++) {

    for(int j = 0; j < i; j++) {

      if(Intersect(circles[i], circles[j])) {

        auto get = Crosspoint(circles[i], circles[j]);

        crossed.push_back(get.first);

        crossed.push_back(get.second);

      }

    }

  }

  for(int j = 0; j < N; j++) {

    for(int i = 0; i < 4; i++) {

      auto seg = Segment(curr(rectangle, i), next(rectangle, i));

      if(Intersect(circles[j], seg)) {

        auto get = Crosspoint(circles[j], seg);

        crossed.push_back(get.first);

        crossed.push_back(get.second);

      }

      crossed.push_back(rectangle[i]);

    }

  }



  for(auto &p : crossed) {

    bool isin = true;

    for(auto &c : circles) {

      isin &= (p - c.p).abs() + 1e-5 >= c.r;

    }

    isin &= Contains(rectangle, p) != OUT;

    if(isin) return (true);

  }

  return (false);

}



int main()

{

  while(scanf("%d %d", &N, &W), N) {

    for(int i = 0; i < N; i++) {

      scanf("%d %d %d", &X[i], &Y[i], &H[i]);

    }

    double low = 0, high = 200;

    for(int i = 0; i < 50; i++) {

      double mid = (low + high) * 0.5;

      if(check(mid)) low = mid;

      else high = mid;

    }

    printf("%.10lf\n", low);

  }

}