#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <bitset>
#include <cctype>
#include <cstdio>
#include <string>
#include <vector>
#include <cassert>
#include <cstdlib>
#include <cstring>
#include <iomanip>
#include <sstream>
#include <iostream>
#include <algorithm>

using namespace std;

#define PB push_back
#define MP make_pair
#define AA first
#define BB second
#define OP begin()
#define ED end()
#define SZ size()
#define SORT(x) sort(x.OP,x.ED)
#define SQ(x) ((x)*(x))
#define SSP system("pause")
#define cmin(x,y) x=min(x,y)
#define cmax(x,y) x=max(x,y)
typedef long long LL;
typedef pair<int, int> PII;
const double eps=1e-8;
const double PI=acos(-1.);
const LL MOD = 1000000007;
int sign(double x) {return x<-eps?-1:x>eps;}
struct spt {
	double x,y,z;
	spt(double _x=0,double _y=0,double _z=0) :x(_x),y(_y),z(_z) {}
	spt operator + (spt s) {return spt(x+s.x,y+s.y,z+s.z);}
	spt operator - (spt s) {return spt(x-s.x,y-s.y,z-s.z);}
	spt operator * (double s) {return spt(x*s,y*s,z*s);}
	spt operator / (double s) {return spt(x/s,y/s,z/s);}
	double len() const {return sqrt(SQ(x)+SQ(y)+SQ(z));}
	double operator * (spt s) {return x*s.x+y*s.y+z*s.z;}   //点积dot
	spt operator ^ (spt s) {	//叉积det
		spt ret;
		ret.x=y*s.z-z*s.y;
		ret.y=z*s.x-x*s.z;
		ret.z=x*s.y-y*s.x;
		return ret;
	}
	void output(char *s="") {printf("%s:%.6f %.6f %.6f\n",s,x,y,z);}
	void input() {scanf("%lf%lf%lf",&x,&y,&z);}
} Orz(0,0,0);
spt S,T,V,A,B,C;
double disLP(spt p1,spt p2,spt q) {
	return fabs((p2-p1)*(q-p1)/(p2-p1).len());
}
double disLL(spt p1,spt p2,spt q1,spt q2) {
	spt p=q1-p1,u=p2-p1,v=q2-q1;
	double d=(u*u)*(v*v)-SQ(u*v);
	if(sign(d)==0)return disLP(q1,q2,p1);
	double s=((p*u)*(v*v)-(p*v)*(u*v))/d;
	return disLP(q1,q2,p1+u*s);
}
int isFL(spt p,spt o,spt q1,spt q2,spt &is) {
	double a=o*(q2-p),b=o*(q1-p);
	double d=a-b;
	if(sign(d)==0)return 0;
	is=(q1*a-q2*b)/d;
	return 1;
}
int isFF(spt p1,spt o1,spt p2,spt o2,spt &ip,spt &io) {
	spt e=o1^o2;
	spt v=o1^e;
	double d=o2*v;
	if(sign(d)==0)return 0;
	ip=p1+v*(o2*(p2-p1))/d,io=e;
	return 1;
}
int inner(spt O,spt A,spt B,spt C) {
	double S=((B-A)^(C-A)).len();
	double S1=((A-O)^(B-O)).len();
	double S2=((A-O)^(C-O)).len();
	double S3=((C-O)^(B-O)).len();
	return sign(S-S1-S2-S3)==0;
}
int inner(double o,double a,double b) {
	return sign(max(a,b)-o)>=0&&sign(min(a,b)-o)<=0;
}
int inner(spt O,spt A,spt B) {
	return inner(O.x,A.x,B.x)&&inner(O.y,A.y,B.y)&&inner(O.z,A.z,B.z);
}
int main() {
	//freopen("","r",stdin);
	//freopen("","w",stdout);
	int i,j,k,u,v,w,p,q,r,n,m;
	while(~scanf("%d",&n)) {
		S.input(),T.input();
		V.input();
		double ans=0;
		spt U= (S-T) ^V;
		for(j=0; j<n; j++) {
			A.input(),B.input(),C.input();
			spt D= (B-A) ^ (C-A);
			if(sign(D.len()) ==0) continue;
			if(sign(U.len())==0) {
				//TODO S->T Yu V PingXing
				spt is;
				int f=isFL(A,D,S,S+V,is);
				if(f) {
					ans+=inner(is,A,B,C);
					continue;
				}
				if(sign((S-A)*D))continue;
				spt iAB,iBC,iAC;
				int fAB=isFL(A,D^(A-B),S,S+V,iAB);
				int fBC=isFL(B,D^(B-C),S,S+V,iBC);
				int fAC=isFL(C,D^(C-A),S,S+V,iAC);
				fAB&=inner(iAB,A,B);
				fBC&=inner(iBC,B,C);
				fAC&=inner(iAC,A,C);
				ans+=fAB|fBC|fAC;
				continue;
			}
			if(sign(V*D)==0) {
				if(sign((S-A)*D)==0&&sign((T-A)*D)==0) {
					//TODO V//ABC && STABC on flat
					spt iA,iB,iC;
					int fA=isFL(S,(T-S)^D,A,A+V,iA);
					int fB=isFL(S,(T-S)^D,B,B+V,iB);
					int fC=isFL(S,(T-S)^D,C,C+V,iC);
					double len=(T-S).len();
					double le=0,re=len;
					vector<double>L;
					if(fA)L.PB((iA-S)*(T-S)/len);
					if(fB)L.PB((iB-S)*(T-S)/len);
					if(fC)L.PB((iC-S)*(T-S)/len);
					sort(L.OP,L.ED);
					if(L.SZ<2)continue;
					double pe=L[0],qe=L[L.SZ-1];
					cmax(pe,le);
					cmin(qe,re);
					if(qe>pe)ans+=(qe-pe)/len;
				}
				continue;
			}
			spt SP,TP,iAB,iBC,iAC;
			assert(isFL(A,D,S,S+V,SP));
			assert(isFL(A,D,T,T+V,TP));
			if(inner(SP,A,B,C)&&inner(TP,A,B,C)) {ans+=1; continue;}
			vector<spt>L;
			L.PB(SP),L.PB(TP);
			int fAB=isFL(A,D^(A-B),SP,TP,iAB);
			int fBC=isFL(B,D^(B-C),SP,TP,iBC);
			int fAC=isFL(C,D^(C-A),SP,TP,iAC);
			double len=(SP-TP).len();
			if(fAB&&inner(iAB,SP,TP))for(i=0; i+1<L.SZ; i++)
					if(inner(iAB,L[i],L[i+1])) {L.insert(L.OP+i+1,iAB); break;}
			if(fBC&&inner(iBC,SP,TP))for(i=0; i+1<L.SZ; i++)
					if(inner(iBC,L[i],L[i+1])) {L.insert(L.OP+i+1,iBC); break;}
			if(fAC&&inner(iAC,SP,TP))for(i=0; i+1<L.SZ; i++)
					if(inner(iAC,L[i],L[i+1])) {L.insert(L.OP+i+1,iAC); break;}
			for(i=0; i+1<L.SZ; i++) {
				spt mid=(L[i]+L[i+1])/2;
				if(inner(mid,A,B,C))
					ans+=(L[i+1]-L[i]).len()/len;
			}
		}
		printf("%.8f\n",ans);
	}
	return 0;
}