#include<cstdio>

#include<cstring>

#include<cmath>

#include<algorithm>

using namespace std;

const int maxn=+;

struct Point

{

    double x,y;

} p[maxn];

double a,b;

int n;

double GetPointDistance(Point p1, Point p2)

{

    return sqrt((p1.x-p2.x)*(p1.x-p2.x)+(p1.y-p2.y)*(p1.y-p2.y));

}

double GetNearestDistance(Point PA, Point PB, Point P3)

{

    double a,b,c;

    a=GetPointDistance(PB,P3);

    if(a<=0.00001) return 0.0f;

    b=GetPointDistance(PA,P3);

    if(b<=0.00001) return 0.0f;

    c=GetPointDistance(PA,PB);

    if(c<=0.00001) return a;

    if(a*a>=b*b+c*c) return b;

    if(b*b>=a*a+c*c) return a;

    double l=(a+b+c)/;

    double s=sqrt(l*(l-a)*(l-b)*(l-c));

    return *s/c;

}

int main()

{

    double Max=-;

    double Min=-;

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

    Point T;

    T.x=a;

    T.y=b;

    for(int i=; i<n; i++) scanf("%lf%lf",&p[i].x,&p[i].y);

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

    {

        double MinLen=GetNearestDistance(p[(i+)%n],p[i],T);

        if(Min==-) Min=MinLen;

        else Min=min(Min,MinLen);

        double Len1=sqrt((p[i].x-a)*(p[i].x-a)+(p[i].y-b)*(p[i].y-b));

        double Len2=sqrt((p[(i+)%n].x-a)*(p[(i+)%n].x-a)+(p[(i+)%n].y-b)*(p[(i+)%n].y-b));

        double MaxLen=max(Len1,Len2);

        if(Max==-) Max=MaxLen;

        else Max=max(Max,MaxLen);

    }

    printf("%lf\n",3.1415926*(Max*Max-Min*Min));

    return ;

}