#include <cstdio>
#include <algorithm>
#include <cmath>
typedef long long ll;
const int N = 2000 + 9;
struct Point
{
int x,y;
Point(const int _x = 0,const int _y = 0):
x(_x),y(_y){}
}p[N * 4],S,T;
int n,pre[N],start;
double dis[N*4],v;
inline ll sqr(const int x){return 1ll*x*x;}
inline double Dis(const Point x,const Point y)
{return std::sqrt(sqr(y.x-x.x) + sqr(y.y-x.y));}
inline ll cpr(const Point x,const Point y,const Point z)
{
const ll x1 = y.x - x.x, y1 = y.y - x.y;
const ll x2 = z.x - x.x, y2 = z.y - x.y;
return x1*y2 - x2*y1;
}
bool check(const int up,const int low,const Point x,const Point y)
{
if (up && cpr(x,p[up],y) > 0 || low && cpr(x,p[low],y) < 0) return false;
return true;
}
double Dijkstra()
{
static bool ins[N*4];
for (start = 1; start <= n; ++start)
if (p[start].x >= S.x) break;
for (int i = start--; i <= n; ++i) dis[i] = 99999999.0;
dis[start] = 0; p[start] = S; dis[4*N - 1] = 999999999.0; pre[start] = -1;
while (1) {
int k = 4*N - 1;
for (int i = start; i <= n; ++i)
if (!ins[i] && dis[k] > dis[i]) k = i;
if (n == k) return dis[k];
ins[k] = 1;
if (k == 7)
k = 7;
int up = 0,low = 0; double tmp;
for (int i = k + 1; i <= n; ++i) {
if (check(up,low,p[k],p[i]))
if (!ins[i] && dis[i] > (tmp = dis[k] + Dis(p[k],p[i])))
dis[i] = tmp;
if (((i-1)%4+1)&1 && (!up || cpr(p[k],p[up],p[i]) <= 0)) up = i;
else if (!(((i-1)%4+1)&1) && (!low || cpr(p[k],p[low],p[i]) >= 0)) low = i;
if (up && low && cpr(p[k],p[up],p[low]) > 0) break;
}
}
}
int main()
{
#ifndef ONLINE_JUDGE
freopen("2433.in","r",stdin);
freopen("2433.out","w",stdout);
#endif
scanf("%d",&n);
for (int i = 1; i <= n; ++i) {
scanf("%d%d%d%d",&p[i*4-2].x,&p[i*4-2].y,&p[i*4-1].x,&p[i*4-1].y);
p[i*4-3] = Point(p[i*4-2].x,p[i*4-1].y);
p[i*4] = Point(p[i*4-1].x,p[i*4-2].y);
}
scanf("%d%d%d%d",&S.x,&S.y,&T.x,&T.y);
n *= 4;
if (S.x > T.x) std::swap(S,T);
for (; n; --n)
if (p[n].x <= T.x) break;
p[++n] = T;
scanf("%lf",&v);
printf("%.10f\n",Dijkstra()/v);
}
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