#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
struct Vec{
	double x,y;
	Vec(double X=0,double Y=0):x(X),y(Y){}
	friend Vec operator+(const Vec a,const Vec b){
		return Vec(a.x+b.x,a.y+b.y);
	}
	friend Vec operator-(const Vec a,const Vec b){
		return Vec(a.x-b.x,a.y-b.y);
	}
	Vec operator*(const double k)const{
		return Vec(x*k,y*k);
	}
	Vec operator/(const double k)const{
		return Vec(x/k,y/k);
	}
	friend double dot(const Vec a,const Vec b){
		return a.x*b.x+a.y*b.y;
	}
	friend double cross(const Vec a,const Vec b){
		return a.x*b.y-a.y*b.x;
	}
	double norm(){return x*x+y*y;}
	double dis(){return sqrt(norm());}
	Vec rotate(){return Vec(y,-x);}
};
struct Circ{
	Vec p;double r;
	Circ(Vec P,double R):p(P),r(R){}
	bool cont(Vec a){return (a-p).norm()<=r*r;}
};
struct Line{
	Vec p,v;
	Line(Vec P,Vec V):p(P),v(V){}
	friend Vec line_inter(Line a,Line b){
		double t=cross((b.p-a.p),b.v)/cross(a.v,b.v);
		return a.p+a.v*t;
	}
};
mt19937 rng(random_device{}());
Circ circum_circ(Vec a,Vec b,Vec c){
	Line lab((a+b)/2,((b-a)/2).rotate());
	Line lac((a+c)/2,((c-a)/2).rotate());
	Vec p=line_inter(lab,lac);
	return Circ(p,(p-a).dis());
}
Circ circum_circ(Vec a,Vec b){
	return Circ((a+b)/2,(b-a).dis()/2);
}
const int P=2147483647,B=233811181,N=2003;
int n,k,st;
int gen(){
	int t=st;
	st=((ll)st*B+1)%P;
	return t;
}
double f[N][N];
double cost[N][N];
int pre[N][N];
Vec arr[N];
int main(){
	scanf("%d%d%d",&n,&k,&st);
	for(int i=1;i<=n;++i){
		arr[i].x=gen();
		arr[i].y=gen();
	}
	for(int l=1;l<=n;++l){
		Circ cur=Circ(arr[l],0);
		cost[l][l]=0;
		for(int i=l+1;i<=n;++i){
			if(!cur.cont(arr[i])){
				cur=Circ(arr[i],0);
				for(int j=l;j<i;++j){
					if(cur.cont(arr[j])) continue;
					cur=circum_circ(arr[i],arr[j]);
					for(int k=l;k<j;++k){
						if(cur.cont(arr[k])) continue;
						cur=circum_circ(arr[i],arr[j],arr[k]);
					}
				}
			}
			cost[l][i]=cur.r;
		}
	}
	for(int i=1;i<=n;++i){
		pre[i][1]=1;
		for(int j=2;j<=i;++j){
			if(fabs(cost[j][i]-cost[j-1][i])<1e-10) pre[i][j]=pre[i][j-1];
			else pre[i][j]=j;
		}
	}
	for(int i=0;i<=k;++i)
		for(int j=0;j<=n;++j) f[i][j]=1e18;
	f[0][0]=0;
	for(int i=1;i<=k;++i)
		for(int j=1;j<=n;++j)
			for(int k=j;k;){
				double tmp=f[i-1][k-1]+cost[k][j];
				if(f[i][j]>tmp) f[i][j]=tmp;
				if(pre[j][k]==k) --k;
				else k=pre[j][k];
			}
	printf("%.10lf\n",f[k][n]);
	return 0;
}