#include<bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)n;i++)
#define all(c) (c).begin(),(c).end()
#define pb push_back
#define dbg(...) do{cerr<<__LINE__<<": ";dbgprint(#__VA_ARGS__, __VA_ARGS__);}while(0);

using namespace std;

namespace std{template<class S,class T>struct hash<pair<S,T>>{size_t operator()(const pair<S,T>&p)const{return ((size_t)1e9+7)*hash<S>()(p.first)+hash<T>()(p.second);}};template<class T>struct hash<vector<T>>{size_t operator()(const vector<T> &v)const{size_t h=0;for(auto i : v)h=h*((size_t)1e9+7)+hash<T>()(i)+1;return h;}};}
template<class T>ostream& operator<<(ostream &os, const vector<T> &v){os<<"[ ";rep(i,v.size())os<<v[i]<<(i==v.size()-1?" ]":", ");return os;}template<class T>ostream& operator<<(ostream &os,const set<T> &v){os<<"{ "; for(const auto &i:v)os<<i<<", ";return os<<"}";}
template<class T,class U>ostream& operator<<(ostream &os,const map<T,U> &v){os<<"{";for(const auto &i:v)os<<" "<<i.first<<": "<<i.second<<",";return os<<"}";}template<class T,class U>ostream& operator<<(ostream &os,const pair<T,U> &p){return os<<"("<<p.first<<", "<<p.second<<")";}
void dbgprint(const string &fmt){cerr<<endl;}template<class H,class... T>void dbgprint(const string &fmt,const H &h,const T&... r){cerr<<fmt.substr(0,fmt.find(","))<<"= "<<h<<" ";dbgprint(fmt.substr(fmt.find(",")+1),r...);}
typedef long long ll;typedef vector<int> vi;typedef pair<int,int> pi;
const double EPS = 1e-12, INF = 1e12, PI = acos(-1.0);
typedef complex<long double> P;
namespace std{
	bool operator<(const P& a, const P& b){
		return real(a) != real(b) ? real(a) < real(b) : imag(a) < imag(b);
	}
}
inline long double cross(const P& a, const P& b){ return imag(conj(a)*b); }
inline long double dot(const P& a, const P& b){ return real(conj(a)*b); }
struct L : public vector<P>{
	L(const P &a, const P &b) {
		push_back(a); push_back(b);
	}
};
typedef vector<P> G;
inline int ccw(P a, P b, P c) {
	b -= a; c -= a;
	if(cross(b, c) >  EPS)   return +1;      // counter clockwise
	if(cross(b, c) < -EPS)   return -1;      // clockwise
	if(dot(b, c)   < -EPS)   return +2;      // c--a--b on line
	if(norm(b)+EPS <norm(c)) return -2;      // a--b--c on line
	return 0;                                   // c is between a and b (inclusive)
}
P crosspoint(const L &l, const L &m) {
	long double A = cross(l[1] - l[0], m[1] - m[0]);
	long double B = cross(l[1] - l[0], l[1] - m[0]);
	if (abs(A) < EPS && abs(B) < EPS) return m[0]; // same line
	if (abs(A) < EPS) assert(false); // !!!PRECONDITION NOT SATISFIED!!!
	return m[0] + B / A * (m[1] - m[0]);
}
#define curr(P, i) P[i]
#define next(P, i) P[(i+1)%P.size()]
long double area2(const G& g) {
	long double A = 0;
	for (int i = 0; i < g.size(); ++i) 
		A += cross(curr(g, i), next(g, i));
	return A;
}
G convex_cut(const G& g, const L& l) {
	G Q;
	for (int i = 0; i < g.size(); ++i) {
		P A = curr(g, i), B = next(g, i);
		if (ccw(l[0], l[1], A) != -1) Q.push_back(A);
		if (ccw(l[0], l[1], A)*ccw(l[0], l[1], B) < 0)
		Q.push_back(crosspoint(L(A, B), l));
	}
	return Q;
}
int main(){
	cin.tie(0); cin.sync_with_stdio(0);
	int n, d, v;
	while(cin >> n >> d >> v, n){
		G g;
		long double ans = 0;
		rep(i, n){ int x, y; cin >> x >> y; g.emplace_back(x, y); }
		rep(i, n){
			long double lo = 0, hi = 4000, mid;
			rep(it, 100){
				mid = (lo + hi) / 2;
				L l(g[(i + 1) % n], g[i]);
				P p = (l[0] - l[1]) * P(0, mid / abs(l[0] - l[1]));
				l[0] += p;
				l[1] += p;
				G h = convex_cut(g, l);
				if(area2(h) * d / 2 >= v - EPS) hi = mid;
				else lo = mid;
			}
			ans = max(ans, lo);
		}
		printf("%.20f\n", (double)ans);
	}
	return 0;
}


Measured memory_bytes: 3252