#include <bits/stdc++.h>
using namespace std;
#define REP(i,n) for(int i=0;i<(int)(n);++i)
#define FOR(i,c) for(__typeof((c).begin())i=(c).begin();i!=(c).end();++i)
#define ALL(c) (c).begin(), (c).end()
#define valid(y,x,h,w) (0<=y&&y<h&&0<=x&&x<w)
#define tpl(...) make_tuple(__VA_ARGS__)
const int INF = 0x3f3f3f3f;
const long double EPS = 1e-12;
#define double long double
const double PI = acos(-1);
typedef long long ll;
typedef pair<int,int> pii;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; }
template<class T>ostream&operator<<(ostream &o,const vector<T>&t){o<<'[';FOR(i,t){if(i!=t.begin())o<<',';o<<*i;}return o<<']';}
template<class S,class T>ostream&operator<<(ostream &o,const pair<S,T>&t){return o<<'('<<t.first<<','<<t.second<<')';}
template<int N,class Tp>void output(ostream&,const Tp&){}
template<int N,class Tp,class,class ...Ts>void output(ostream &o,const Tp&t){if(N)o<<',';o<<get<N>(t);output<N+1,Tp,Ts...>(o,t);}
template<class ...Ts>ostream&operator<<(ostream&o,const tuple<Ts...>&t){o<<'(';output<0,tuple<Ts...>,Ts...>(o,t);return o<<')';}
template<class T>void output(T t,char z=10){if(t<0)t=-t,putchar(45);int c[20];
int k=0;while(t)c[k++]=t%10,t/=10;for(k||(c[k++]=0);k;)putchar(c[--k]^48);putchar(z);}
template<class T>void outputs(T t){output(t);}
template<class S,class ...T>void outputs(S a,T...t){output(a,32);outputs(t...);}
template<class T>void output(T *a,int n){REP(i,n)cout<<a[i]<<(i!=n-1?',':'\n');}
template<class T>void output(T *a,int n,int m){REP(i,n)output(a[i],m);}
template<class T>bool input(T &t){int n=1,c;for(t=0;!isdigit(c=getchar())&&~c&&c-45;);
if(!~c)return 0;for(c-45&&(n=0,t=c^48);isdigit(c=getchar());)t=10*t+c-48;t=n?-t:t;return 1;}
template<class S,class ...T>bool input(S&a,T&...t){input(a);return input(t...);}

template<class T>
struct Pt {
  T x,y;
  Pt(T x=T(), T y=T()) :x(x),y(y) {}
  bool operator<(const Pt &p) const { return x!=p.x?x<p.x:y<p.y; }
  bool operator==(const Pt &p) const { return x==p.x&&y==p.y; }
  Pt operator+=(const Pt &p) { x+=p.x, y+=p.y; return *this; }
  Pt operator-=(const Pt &p) { x-=p.x, y-=p.y; return *this; }
  Pt operator*=(const Pt &p) { T t=x;x=x*p.x-y*p.y,y=t*p.y+y*p.x; return *this;}
  Pt operator*=(const T &v) { x*=v; y*=v; return *this;}
  friend ostream& operator<<(ostream& os, const Pt &p) {return os<<'('<<p.x<<','<<p.y<<')';}
  friend istream& operator>>(istream& is, Pt &p) {return is>>p.x>>p.y;}

  Pt operator+(const Pt &p) const { return Pt(*this)+=p; }
  Pt operator-(const Pt &p) const { return Pt(*this)-=p; }
  Pt operator*(const Pt &p) const { return Pt(*this)*=p; }
  Pt operator*(const T &v) const { return Pt(*this)*=v; }
  friend Pt operator*(const T &v, const Pt &p) { return p*v; }
  bool operator!=(const Pt &p) const { return !(*this == p); }

  T abs() const { return hypot(x,y); }
  T norm() const { return x*x+y*y; }
  T arg() const { return atan2(y,x); }
  T dot(const Pt &p) const { return x*p.x+y*p.y; }
  T det(const Pt &p) const { return x*p.y-y*p.x; }
  friend T abs(const Pt &p) { return p.abs(); }
  friend T norm(const Pt &p) { return p.norm(); }
  friend T arg(const Pt &p) { return p.arg(); }
  friend T dot(const Pt &p, const Pt &q) { return p.dot(q); }
  friend T det(const Pt &p, const Pt &q) { return p.det(q); }
};

int sig(double r) {return r<-EPS?-1:r>EPS?1:0;}
int sig(ll r) {return r<0?-1:r>0?1:0;}
bool eq(double a, double b) {return sig(a-b)==0;}
bool eq(ll a, ll b) {return a==b;}

template<class T>int ccw(Pt<T> a, Pt<T> b, Pt<T> c); // 2(c--a--b), -2(a--b--c), 0(a=-c-=b)

template<> int ccw(Pt<ll> a, Pt<ll> b, Pt<ll> c) {
  b -= a; c -= a;
  return det(b,c) ? sig(det(b,c)) : dot(b,c)<0 ? 2 : (0<b.norm()&&b.norm()<c.norm()) ? -2 : 0;
}
template<> int ccw(Pt<double> a, Pt<double> b, Pt<double> c) {
  b -= a; c -= a;
  if (det(b,c)) return sig(det(b,c));
  if (sig(dot(b, c)) == -1) return +2; // c--a--b
  if (EPS < b.norm() && b.norm() < c.norm()-EPS) return -2; // a--b--c
  return 0;
}

typedef Pt<double> P;

class L {
  vector<P> v;
public:
  L(const P &a, const P &b) : v({a,b,b-a}) {}
  const P operator[](int i) const { return v[i]; }
  void sub(const P&p) { v[0] -= p; v[1] -= p; }
  friend ostream &operator<<(ostream &os, const L &l) {
    return os << l[0] << "->" << l[1];
  }
};

bool iSS(const L &s, const L &t) {
  return ccw(s[0],s[1],t[0])*ccw(s[0],s[1],t[1]) <= 0 &&
         ccw(t[0],t[1],s[0])*ccw(t[0],t[1],s[1]) <= 0;
}
bool iSP(const L &s, const P &p) {

  return sig(abs(s[0]-p)+abs(s[1]-p)-abs(s[2])) <= 0;
};

P crosspoint(const L &l, const L &m) {
  auto A = det(l[2],m[2]);
  auto B = det(l[2],l[1]-m[0]);
  if (!sig(A) && !sig(B)) return m[0];// same line
  if (!sig(A)) assert(0); // !!!PRECONDITION NOT SATISFIED!!!
  return m[0] + B/A*m[2];
}

typedef vector<int> Edges;
typedef vector<Edges> Graph;

Graph segmentArrangement(const vector<L> &ss, vector<P> &ps) {
  int n = ss.size();
  REP(i,n) {
    ps.push_back( ss[i][0] );
    ps.push_back( ss[i][1] );
    for (int j = i+1; j < n; ++j)
      if (iSS(ss[i], ss[j]))
        ps.push_back( crosspoint(ss[i], ss[j]) );
  }
  sort(ALL(ps)); ps.erase(unique(ALL(ps)), ps.end());
  Graph g(ps.size());
  REP(i,ss.size()) {
    vector<pair<double,int> > v;
    REP(j,ps.size()) if (iSP(ss[i], ps[j])) {
      v.emplace_back(norm(ss[i][0]-ps[j]), j);
    }
    sort(ALL(v));
    REP(j,(int)v.size()-1) {
      int a = v[j].second, b = v[j+1].second;
      g[a].push_back(b); g[b].push_back(a);
    }
  }
  return g;
}


int main() {
  int n,m;
  while(input(n,m)) {
    vector<L> ss;
    double sum = 0;
    REP(i,n) {
      P a,b; cin >> a >> b;
      ss.emplace_back(a,b);
      sum += (a-b).abs();
    }
    vector<P> ps(m+2);
    REP(i,m+2) cin >> ps[i];
    vector<P> p(ps);
    Graph g = segmentArrangement(ss,ps);
    vector<int> p2ps(m+2,-1);
    vector<int> ps2p(ps.size(),-1);
    REP(i,m+2) {
      REP(j,ps.size())
        if (norm(p[i]-ps[j]) < EPS) {
          assert(p2ps[i] == -1);
          assert(ps2p[j] == -1);
          p2ps[i] = j;
          ps2p[j] = i;
        }
    }

    vector<bool> fg(ps.size()), fs(ps.size());
    {
      queue<int> Q;
      Q.push(p2ps[m+1]);
      bool ng = 0;
      fg[p2ps[m+1]] = 1;
      while(!Q.empty()) {
        int v = Q.front(); Q.pop();
        if (ps2p[v] != -1 && ps2p[v] < m) continue;
        if (ps2p[v] == m) {
          ng = 1;
          break;
        }
        FOR(it, g[v]) if (!fg[*it]) {
          fg[*it] = 1;
          Q.push(*it);
        }
      }
      if (ng) {
        puts("-1");
        continue;
      }
    }
    double ans = 0;
    {
      queue<int> Q;
      Q.push(p2ps[m]);
      fs[p2ps[m]] = 1;
      while(!Q.empty()) {
        int v = Q.front(); Q.pop();
        // cout << ps2p[v] << " " << ps[v] << " " << g[v].size() << endl;

        FOR(it, g[v]) {
          if (!fg[v] || !fg[*it])
            ans += abs(ps[v] - ps[*it]);
          if (!fs[*it] && !fg[v]) {
            fs[*it] = 1;
            Q.push(*it);
          }
        }
      }
    }
    ans = sum - ans / 2;
    printf("%.10Lf\n", ans);
  }
}

Measured memory_bytes: 2476