#include<bits/stdc++.h>
using namespace std;
using ll=long long;
const double eps=1e-6;
double r,d;
double f(double x){
    return 2*sqrt(max(0.0,r*r-x*x))*(x-d)*(x-d);
}
double calc(double l,double r){
    return (r-l)*(f(l)+f(r)+4*f((l+r)/2))/6;
}
double solve(double l,double r,double eps,double ans,int d=8){
    // fprintf(stderr,"%lf %lf %lf %lf\n",l,r,eps,ans);
    double mid=(l+r)/2,fl=calc(l,mid),fr=calc(mid,r);
    if(abs(fl+fr-ans)<eps*15*max(1.0,ans))return fl+fr+(fl+fr-ans)/15;
    return solve(l,mid,eps,fl,d-1)+solve(mid,r,eps,fr,d-1);
}
using vec=complex<ll>;
const int N=5e3+10;
vec a[N];
ll dot(vec a,vec b){
    return real(a)*real(b)+imag(a)*imag(b);
}
ll cross(vec a,vec b){
    return dot(a,b*vec(0,-1));
}
ll dis2(vec a){
    return dot(a,a);
}
int n,m;
void read(vec &a){
    static ll x,y;
    scanf("%lld%lld",&x,&y);
    a=vec(x*2,y*2);
}
bool isin(vec o){
    for(int i=1;i<=n;i++){
        if(cross(o-a[i],a[i%n+1]-a[i])>0)return 0;
    }
    return 1;
}
double calc(vec a,vec b,vec x){
    if(dot(x-a,b-a)<0)return sqrt(dis2(x-a));
    if(dot(x-b,a-b)<0)return sqrt(dis2(x-b));
    return abs(cross(x-a,x-b))/sqrt(dis2(a-b));
}
int main(){
    scanf("%d%d",&n,&m);
    for(int i=1,x,y;i<=n;i++){
        read(a[i]);
    }
    for(;m--;){
        vec s,t;
        read(s),read(t);
        vec cur=s-t;
        double x=real(cur),y=imag(cur);
        r=sqrt(x*x+y*y)/2;
        vec o=(s+t)/2ll;
        if(!isin(o)){
            d=INFINITY;
            for(int i=1;i<=n;i++){
                d=min(d,calc(a[i],a[i%n+1],o));
            }
        }else d=0;
        d/=sqrt(2);
        // cerr<<r<<' '<<d<<endl;
        double ans=solve(-r,r,eps,calc(-r,r));
        ans*=2;
        static const double pi=acos(-1);
        ans/=pi*r*r;
        printf("%.9lf\n",ans/4);
    }
    return 0;
}