//By SiriusRen

#include <bits/stdc++.h>

using namespace std;

const int N=;

const double eps=1e-;

int card,n,m,k;

double a,b,r,xx,yy,theta,Ans;

struct Point{

    double x,y;Point(){}

    Point(double X,double Y){x=X,y=Y;}

}point[N],tubao[N];

bool cmp1(Point a,Point b){if(abs(a.x-b.x)>eps)return a.x<b.x;return a.y<b.y;}

double cross(Point a,Point b,Point c){

    return (a.x-c.x)*(b.y-c.y)-(a.y-c.y)*(b.x-c.x);

}

double dis(Point a,Point b){

    return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));

}

int main(){

    scanf("%d%lf%lf%lf",&card,&a,&b,&r);

    Ans+=*acos(-)*r;

    a=a-*r,b=b-*r;

    for(int i=;i<=card;i++){

        scanf("%lf%lf%lf",&xx,&yy,&theta);

        point[++n]=Point(xx-sin(theta)*a/-cos(theta)*b/,yy+cos(theta)*a/-sin(theta)*b/);

        point[++n]=Point(xx-sin(theta)*a/+cos(theta)*b/,yy+cos(theta)*a/+sin(theta)*b/);

        point[++n]=Point(xx+sin(theta)*a/-cos(theta)*b/,yy-cos(theta)*a/-sin(theta)*b/);

        point[++n]=Point(xx+sin(theta)*a/+cos(theta)*b/,yy-cos(theta)*a/+sin(theta)*b/);

    }

    sort(point+,point++n,cmp1);

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

        while(m>&&cross(tubao[m],point[i],tubao[m-])<eps)m--;

        tubao[++m]=point[i];

    }k=m;

    for(int i=n-;i;i--){

        while(m>k&&cross(tubao[m],point[i],tubao[m-])<eps)m--;

        tubao[++m]=point[i];

    }

    for(int i=;i<m;i++)Ans+=dis(tubao[i],tubao[i+]);

    printf("%.2lf\n",Ans);

}