#include<bits/stdc++.h>

#define REP(i,s,n) for(int i=s;i<n;i++)
#define rep(i,n) REP(i,0,n)
#define EPS (1e-10)
#define equals(a,b) (fabs((a)-(b))<EPS)

using namespace std;

static const int COUNTER_CLOCKWISE = 1;
static const int CLOCKWISE = -1;
static const int ONLINE_BACK = 2;
static const int ONLINE_FRONT = -2;
static const int ON_SEGMENT = 0;


class Point{
public:
  double x,y;

  Point(double x = 0,double y = 0): x(x),y(y){}

  Point operator + (Point p){return Point(x+p.x,y+p.y);}
  Point operator - (Point p){return Point(x-p.x,y-p.y);}
  Point operator * (double a){return Point(a*x,a*y);}
  Point operator / (double a){return Point(x/a,y/a);}
  Point operator * (Point a){ return Point(x * a.x - y * a.y, x * a.y + y * a.x); }

  bool operator < (const Point& p) const{ return !equals(x,p.x)?x<p.x:y<p.y; }

  bool operator == (const Point& p)const{ return fabs(x-p.x) < EPS && fabs(y-p.y) < EPS; }

};

struct Segment{
  Point p1,p2;
  Segment(Point p1 = Point(),Point p2 = Point()):p1(p1),p2(p2){}
  bool operator == (const Segment& p)const { return p.p1 == p1 && p.p2 == p2; }
};

typedef Point Vector;
typedef Segment Line;
typedef vector<Point> Polygon;

ostream& operator << (ostream& os,const Point& a){ os << "(" << a.x << "," << a.y << ")"; }

ostream& operator << (ostream& os,const Segment& a){ os << "( " << a.p1 << " , " << a.p2 << " )"; }

double dot(Point a,Point b){ return a.x*b.x + a.y*b.y; }

double cross(Point a,Point b){ return a.x*b.y - a.y*b.x; }

double norm(Point a){ return a.x*a.x+a.y*a.y; }

double abs(Point a){ return sqrt(norm(a)); }

//rad は角度をラジアンで持たせること
Point rotate(Point a,double rad){ return Point(cos(rad)*a.x - sin(rad)*a.y,sin(rad)*a.x + cos(rad)*a.y); }

// 度をラジアンに変換
double toRad(double agl){ return agl*M_PI/180.0; }

// a => prev, b => cur, c=> next
// prev から cur へ行って next へ行く際の角度を求める
double getArg(Point a,Point b,Point c){
  double arg1 = atan2(b.y-a.y,b.x-a.x);
  double arg2 = atan2(c.y-b.y,c.x-b.x);
  double arg = fabs( arg1 - arg2 );
  while( arg > M_PI ) arg -= 2.0 * M_PI;
  return fabs(arg);
}

int ccw(Point p0,Point p1,Point p2){
  Point a = p1-p0;
  Point b = p2-p0;
  if(cross(a,b) > EPS)return COUNTER_CLOCKWISE;
  if(cross(a,b) < -EPS)return CLOCKWISE;
  if(dot(a,b) < -EPS)return ONLINE_BACK;
  if(norm(a) < norm(b))return ONLINE_FRONT;
  return ON_SEGMENT;
}

Point projection(Line l,Point p) {
  double t = dot(p-l.p1, l.p1-l.p2) / norm(l.p1-l.p2);
  return l.p1 + (l.p1-l.p2)*t;
}

double distanceLP(Line l, Point p) {
  return abs(p - projection(l, p));
}

double cross3p(Point p,Point q,Point r){ return (r.x-q.x) * (p.y -q.y) - (r.y - q.y) * (p.x - q.x); }
  
bool collinear(Point p,Point q,Point r) { return fabs(cross3p(p,q,r)) < EPS; }
  
bool ccwtest(Point p,Point q,Point r){ return cross3p(p,q,r) > 0; }
 
bool onSegment(Point p,Point q,Point r){
  return collinear(p,q,r) && equals(sqrt(pow(p.x-r.x,2)+pow(p.y-r.y,2)) + sqrt(pow(r.x-q.x,2) + pow(r.y-q.y,2) ),sqrt(pow(p.x-q.x,2)+pow(p.y-q.y,2)) ) ;
}

#define pow2(a) ((a)*(a))
typedef pair<double,double> dd;
const double DINF = 1e20;
bool LT(double a ,double b){ return !equals(a,b) && a < b; }
bool LTE(double a,double b){ return  equals(a,b) || a < b; }


dd calc(double x1,double y1,double vx1,double vy1,
        double x2,double y2,double vx2,double vy2,double r){
  double VX = (vx1-vx2), X = (x1-x2), VY = (vy1-vy2), Y = (y1-y2);
  double a = pow2(VX) + pow2(VY), b = 2*(X*VX+Y*VY), c = pow2(X) + pow2(Y) - pow2(r);
  dd ret = dd(DINF,DINF);
  double D = b*b - 4 * a * c;

  if( LT(D,0.0) ) return ret;

  if( equals(a,0.0) ) {
    if( equals(b,0.0) ) return ret;
    if( LT(-c/b,0.0)  ) return ret;
    ret.first = - c / b;
    return ret;
  }

  if( equals(D,0.0) ) D = 0;
  ret.first  = ( -b - sqrt( D ) ) / ( 2 * a );
  ret.second = ( -b + sqrt( D ) ) / ( 2 * a );
  if( !equals(ret.first,ret.second) && ret.first > ret.second ) swap(ret.first,ret.second);
  return ret;
}


const Point ZERO = Point(0,0);
//線分ABと中心がcp,半径rの円との共通部分の面積を求める
inline double calculator_TypeA(Point A,Point B,Point cp,double r){
  A = A - cp, B = B - cp; 
  if( A == ZERO || B == ZERO ) return 0;
  double cross_value = cross(A,B);
  if( equals(cross_value,0.0) ) return 0;
  double sig = LT(cross_value,0.0) ? -1 : 1;
  Segment AB = Segment(A,B);
  double nearest_distance = distanceLP(AB,ZERO);
  double distance_OA = abs(A);
  double distance_OB = abs(B);

  if( LTE(0.0,r-distance_OA) && LTE(0.0,r-distance_OB) && LTE(0.0,r-nearest_distance) ) {
    return sig * fabs( cross_value / 2.0 );
  } else if( LTE(0.0,distance_OA-r) && LTE(0.0,distance_OB-r) && LTE(0.0,nearest_distance-r) ) {
    return sig * ( r * r * (M_PI-getArg(A,ZERO,B)) ) / 2.0;
  } else if( LTE(0.0,distance_OA-r) && LTE(0.0,distance_OB-r) && LT(0.0,r-nearest_distance) ) {

    Point proj_p = projection(AB,ZERO);
    if( onSegment(AB.p1,AB.p2,proj_p) ) {
      Vector e = ( A - B ) / abs( A - B );
      dd tmp = calc(A.x,A.y,e.x,e.y,0,0,0,0,r);
      Point r_p1 = A + e * tmp.first;
      Point r_p2 = A + e * tmp.second; 
      double ret = r * r * (M_PI-getArg(B,ZERO,A)) / 2.0;
      double subtract = r * r * (M_PI-getArg(r_p1,ZERO,r_p2)) / 2.0 - fabs(cross(r_p1,r_p2))/2.0 ;
      return sig * ( ret - subtract );
    } else {
      return sig * ( r * r * (M_PI-getArg(B,ZERO,A)) ) / 2.0; 
    }
  } else {

    if( LT(distance_OB-r,0.0) ) swap(A,B);
    Vector e = ( A - B ) / abs( A - B );
    dd tmp = calc(A.x,A.y,e.x,e.y,0,0,0,0,r);
    Point r_p1 = A + e * tmp.first;
    Point r_p2 = A + e * tmp.second; 
    if( onSegment(A,B,r_p2) ) r_p1 = r_p2;
    double ret = fabs(cross(r_p1,A)) * 0.5;
    ret += r * r * (M_PI-getArg(r_p1,ZERO,B)) * 0.5;
    return sig * ret;
  }
  assert(false);
}

double calc(const Polygon &poly,Point cp,double r){
  double sum = 0;
  rep(i,(int)poly.size()){  
    sum += calculator_TypeA(poly[i],poly[(i+1)%(int)poly.size()],cp,r);
  }
  return fabs(sum);
}


int N,R;
Polygon ps;

double compute(int R){ return calc(ps,ZERO,R) - ((R-1>0)?calc(ps,ZERO,R-1):0); }

int main(){
  cin >> N >> R;
  ps.resize(N);
  rep(i,N) cin >> ps[i].x >> ps[i].y;
  double area = 0;
  for(int r=2;r<=R;r+=2) area += ( r * r * M_PI ) - ( (r-1) * (r-1) * M_PI );
  for(int r=1;r<=R;r++){
    if( r & 1 ) area += compute(r);
    else        area -= compute(r);
  }
  printf("%.10lf\n",area);
  return 0;
}

Measured memory_bytes: 1332