#include <cstdio>

 #include <cstring>

 #include <cmath>

 #include <iostream>

 #include <iomanip>

 #include <vector>

 #include <algorithm>

 using namespace std;

 typedef double db;

 const db eps=1e-;

 const db pi=acos(-);

 int sign(db k){

     if (k>eps) return ; else if (k<-eps) return -; return ;

 }

 int cmp(db k1,db k2){return sign(k1-k2);}

 struct point{

     db x,y;

     point operator + (const point &k1) const{return (point){k1.x+x,k1.y+y};}

     point operator - (const point &k1) const{return (point){x-k1.x,y-k1.y};}

     point operator * (db k1) const{return (point){x*k1,y*k1};}

     point operator / (db k1) const{return (point){x/k1,y/k1};}

     db abs(){ return sqrt(x*x+y*y);}

 };

 db cross(point k1,point k2){return k1.x*k2.y-k1.y*k2.x;}

 db dot(point k1,point k2){return k1.x*k2.x+k1.y*k2.y;}

 point getLL(point k1,point k2,point k3,point k4){

     db w1=cross(k1-k3,k4-k3),w2=cross(k4-k3,k2-k3); return (k1*w2+k2*w1)/(w1+w2);

 }

 int intersect(db l1,db r1,db l2,db r2){

     if (l1>r1) swap(l1,r1); if (l2>r2) swap(l2,r2); return cmp(r1,l2)!=-&&cmp(r2,l1)!=-;

 }

 int checkSS(point k1,point k2,point k3,point k4){

     return intersect(k1.x,k2.x,k3.x,k4.x)&&intersect(k1.y,k2.y,k3.y,k4.y)&&

            sign(cross(k3-k1,k4-k1))*sign(cross(k3-k2,k4-k2))<=&&

            sign(cross(k1-k3,k2-k3))*sign(cross(k1-k4,k2-k4))<=;

 }

 struct line{

     point p[];

     line(point k1,point k2){p[]=k1; p[]=k2;}

 };

 double l,r,y;

 point p[];

 int n;

 point s1,t1,s2,t2;

 //离散化+前缀和。

 vector<db> v,a,b;

 int pre[];

 int main(){

     ios::sync_with_stdio(false);

     cout<<fixed<<setprecision();

     while (cin>>l>>r>>y&&(l||r||y)){

         s1={l,y};t1={r,y};

         cin>>l>>r>>y;

         s2={l,y};t2={r,y};

         v.push_back(l);

         v.push_back(r);

         cin>>n;

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

             cin>>l>>r>>y;

             p[i]={l,y};

             p[i+]={r,y};

         }

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

             if(cmp(s1.y,p[i].y)==&&cmp(p[i].y,s2.y)==){//在中间

                 point tmp = getLL(t1,p[i],s2,t2);

                 v.push_back(tmp.x);//-1

                 a.push_back(tmp.x);

                 tmp = getLL(s1,p[i+],s2,t2);

                 v.push_back(tmp.x);//+1

                 b.push_back(tmp.x);

             }

         }

         sort(v.begin(),v.end());

         v.erase(unique(v.begin(),v.end()),v.end());

         for(int i=;i<a.size();i++){

             int id = lower_bound(v.begin(),v.end(),a[i])-v.begin();

             pre[id]--;

         }

         for(int i=;i<b.size();i++){

             int id = lower_bound(v.begin(),v.end(),b[i])-v.begin();

             pre[id]++;

         }

         int id1 = lower_bound(v.begin(),v.end(),s2.x)-v.begin();

         int id2 = lower_bound(v.begin(),v.end(),t2.x)-v.begin();

         for(int i=;i<v.size();i++){

             pre[i]+=pre[i-];

         }

         db ans = ;

         for(int l=id1,r;l<=id2;l=r+){

             r=l;

             while (r<id2&&pre[r]>=)

                 r++;

             ans=max(ans,v[r]-v[l]);

         }

         if(cmp(ans,0.00)==){

             cout<<"No View"<<endl;

         } else {

             cout << ans << endl;

         }

         v.clear();

         a.clear();

         b.clear();

         memset(pre,, sizeof(pre));

     }

 }

 /**

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  2 6 6

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  */