// Slower C++ solution:
#include <iostream>

#include <algorithm>

#include <cmath>

#include <vector>

#include <complex>

#include <queue>

#include <deque>

#include <set>

#include <map>

#include <unordered_set>

#include <unordered_map>

#include <iomanip>

#include <assert.h>

#include <array>

#include <cstdio>

#include <cstring>

#include <random>

#include <functional>

#include <numeric>

#include <bitset>

#include <fstream>



using namespace std;



#define REP(i,a,b) for(int i=a;i<(int)b;i++)

#define rep(i,n) REP(i,0,n)

#define all(c) (c).begin(), (c).end()

#define zero(a) memset(a, 0, sizeof a)

#define minus(a) memset(a, -1, sizeof a)

template<class T1, class T2> inline bool minimize(T1 &a, T2 b) { return b < a && (a = b, 1); }

template<class T1, class T2> inline bool maximize(T1 &a, T2 b) { return a < b && (a = b, 1); }



typedef long long ll;

int const inf = 1<<29;



const double EPS = 1e-9;



using number = double;



struct point {

  number x, y;

  point operator + (point r) { return point{x + r.x, y + r.y}; }

  point operator + (const point& r) const { return point{x + r.x, y + r.y}; }

  point operator - (point r) { return point{x - r.x, y - r.y}; }

  point operator - (const point& r) const { return point{x - r.x, y - r.y}; }

  point operator * (point r) { return point{x*r.x - y*r.y, x*r.y + r.x*y}; }

  void operator -= (point r) { x -= r.x, y -= r.y; }

  point nml() { return point{x/sqrt(x*x+y*y), y/sqrt(x*x+y*y)}; }

};

point operator * (number k, point p) { return point{k * p.x, k * p.y}; }



struct line {

  point s, t;

};



typedef line segment;



number dot(point a, point b) {

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

}



number cross(point a, point b) {

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

}



number norm(point p) {

  return p.x * p.x + p.y * p.y;

}



struct polygon : public vector<point> {

  number area2() {

    number ret{};

    rep(i, this->size())

      ret += cross((*this)[i],(*this)[(i+1)%this->size()]);

    return abs(ret);

  }

};



int ccw(point a, point b, point c) {

  b -= a, c -= a;

  if(cross(b, c) > +EPS) return +1;

  if(cross(b, c) < -EPS) return -1;

  if(dot(b, c) < -EPS) return +2;

  if(norm(b) < norm(c)) return -2;

  return 0;

}



point crosspoint(const line &l, const line &m) {

  number A = cross(l.t - l.s, m.t - m.s);

  number B = cross(l.t - l.s, l.t - m.s);

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

  if(abs(A) < EPS) assert(false); // !!!PRECONDITION NOT SATISFIED!!!

  return m.s + B / A * (m.t - m.s);

}



polygon convex_cut(polygon& g, line& l) {

  polygon ret{};

  rep(i, g.size()) {

    auto a = g[i], b = g[(i+1)%g.size()];

    if(ccw(l.s, l.t, a) != -1) ret.push_back(a);

    if(ccw(l.s, l.t, a) * ccw(l.s, l.t, b) < 0)

      ret.push_back(crosspoint(line{a, b}, l));

  }

  return ret;

}



bool compare(polygon& g, number V, number D, int ridx, number height) {

  line l{g[(ridx+1)%g.size()], g[ridx]};

  point v = height * ((l.t - l.s) * point{0, -1}).nml();

  l.s = l.s + v, l.t = l.t + v;

  return convex_cut(g, l).area2() * D < V * 2;

}



int main() {

  int N; number D, V;

  while(cin >> N >> D >> V && (N||D||V)) {

    polygon g{};

    rep(i, N) {

      number x, y; cin >> x >> y;

      g.push_back(point{x, y});

    }



    number ans = 0;



    rep(i, N) {

      number l = 0, h = 114514;

      rep(_, 300) {

        number mid = (l + h) / 2;

        (compare(g, V, D, i, mid) ? l : h) = mid;

      }

      ans = max(ans, l);

    }



    printf("%.10f\n", ans);

  }

  return 0;

}

// Faster C++ solution for the same problem (measured speedup: 1.171731732356886x):
#include <iostream>

#include <algorithm>

#include <cmath>

#include <vector>

#include <complex>

#include <queue>

#include <deque>

#include <set>

#include <map>

#include <unordered_set>

#include <unordered_map>

#include <iomanip>

#include <assert.h>

#include <array>

#include <cstdio>

#include <cstring>

#include <random>

#include <functional>

#include <numeric>

#include <bitset>

#include <fstream>



using namespace std;



#define REP(i,a,b) for(int i=a;i<(int)b;i++)

#define rep(i,n) REP(i,0,n)

#define all(c) (c).begin(), (c).end()

#define zero(a) memset(a, 0, sizeof a)

#define minus(a) memset(a, -1, sizeof a)

template<class T1, class T2> inline bool minimize(T1 &a, T2 b) { return b < a && (a = b, 1); }

template<class T1, class T2> inline bool maximize(T1 &a, T2 b) { return a < b && (a = b, 1); }



typedef long long ll;

int const inf = 1<<29;



const double EPS = 1e-9;



using number = double;



struct point {

  number x, y;

  point operator + (point r) { return point{x + r.x, y + r.y}; }

  point operator + (const point& r) const { return point{x + r.x, y + r.y}; }

  point operator - (point r) { return point{x - r.x, y - r.y}; }

  point operator - (const point& r) const { return point{x - r.x, y - r.y}; }

  point operator * (point r) { return point{x*r.x - y*r.y, x*r.y + r.x*y}; }

  void operator -= (point r) { x -= r.x, y -= r.y; }

  point nml() { return point{x/sqrt(x*x+y*y), y/sqrt(x*x+y*y)}; }

};

point operator * (number k, point p) { return point{k * p.x, k * p.y}; }



struct line {

  point s, t;

};



typedef line segment;



number dot(point a, point b) {

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

}



number cross(point a, point b) {

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

}



number norm(point p) {

  return p.x * p.x + p.y * p.y;

}



struct polygon : public vector<point> {

  number area2() {

    number ret{};

    rep(i, this->size())

      ret += cross((*this)[i],(*this)[(i+1)%this->size()]);

    return abs(ret);

  }

};



int ccw(point a, point b, point c) {

  b -= a, c -= a;

  if(cross(b, c) > +EPS) return +1;

  if(cross(b, c) < -EPS) return -1;

  if(dot(b, c) < -EPS) return +2;

  if(norm(b) < norm(c)) return -2;

  return 0;

}



point crosspoint(const line &l, const line &m) {

  number A = cross(l.t - l.s, m.t - m.s);

  number B = cross(l.t - l.s, l.t - m.s);

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

  if(abs(A) < EPS) assert(false); // !!!PRECONDITION NOT SATISFIED!!!

  return m.s + B / A * (m.t - m.s);

}



polygon convex_cut(polygon& g, line& l) {

  polygon ret{};

  rep(i, g.size()) {

    auto a = g[i], b = g[(i+1)%g.size()];

    if(ccw(l.s, l.t, a) != -1) ret.push_back(a);

    if(ccw(l.s, l.t, a) * ccw(l.s, l.t, b) < 0)

      ret.push_back(crosspoint(line{a, b}, l));

  }

  return ret;

}



bool compare(polygon& g, number V, number D, int ridx, number height) {

  line l{g[(ridx+1)%g.size()], g[ridx]};

  point v = height * ((l.t - l.s) * point{0, -1}).nml();

  l.s = l.s + v, l.t = l.t + v;

  return convex_cut(g, l).area2() * D < V * 2;

}



int main() {

  int N; number D, V;

  while(cin >> N >> D >> V && (N||D||V)) {

    polygon g{};

    rep(i, N) {

      number x, y; cin >> x >> y;

      g.push_back(point{x, y});

    }



    number ans = 0;



    rep(i, N) {

      number l = 0, h = 114514;

      rep(_, 100) {

        number mid = (l + h) / 2;

        (compare(g, V, D, i, mid) ? l : h) = mid;

      }

      ans = max(ans, l);

    }



    printf("%.10f\n", ans);

  }

  return 0;

}