#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <cmath>
 
using namespace std;
 
#define INF 999999999.0
#define MAX_N 1010
#define DIS(a,b) sqrt((pos[a].x-pos[b].x)*(long long)(pos[a].x-pos[b].x)+(pos[a].y-pos[b].y)*(long long)(pos[a].y-pos[b].y))
 
struct POS
{
	int x,y;
} pos[MAX_N];
struct FLAG
{
	int V[MAX_N];
	int cnt;
} Flag[MAX_N];
int n,w;
double m;
bool road[MAX_N][MAX_N];
double dis[MAX_N][MAX_N];
double d[MAX_N][MAX_N];
double sd[MAX_N];
bool vis[MAX_N];
int sID,tID;
 
void dfs(int v,int flagID)
{
	if(v==0) sID=flagID;
	else if(v==n-1) tID=flagID;
	vis[v]=true;
	Flag[flagID].V[Flag[flagID].cnt++]=v;
	for(int i=0;i<n;i++)
	{
		if(!vis[i] && road[v][i]) dfs(i,flagID);
	}
}
 
#define MAX_Q 10000
#define ADD(x) x=(x+1)%MAX_Q
 
double SPFA(int s,int n)
{
	int queue[MAX_Q],front,rear;
	bool inq[MAX_N];
 
	for(int i=0;i<n;i++) sd[i]=INF;
 
	sd[s]=0;
	front=rear=0;
	queue[rear]=s;
	inq[s]=true;
	ADD(rear);
 
	while(front!=rear)
	{
		int q=queue[front];
		ADD(front);
		inq[q]=false;
		for(int u=0;u<n;u++)
		{
			if(sd[u]>sd[q]+d[q][u])
			{
				sd[u]=sd[q]+d[q][u];
				if(inq[u]) continue;
				queue[rear]=u;
				ADD(rear);
				inq[u]=true;
			}
		}
	}
 
	return sd[tID];
}
 
int Main()
{
	freopen("pwrfail.in","r",stdin);
	freopen("pwrfail.out","w",stdout);
 
	scanf("%d%d",&n,&w);
	scanf("%lf",&m);
 
	for(int i=0;i<n;i++)
	{
		int a,b;
 
		scanf("%d%d",&a,&b);
		pos[i].x=a;pos[i].y=b;
	}
 
	for(int i=0;i<n;i++)
	{
		for(int j=0;j<n;j++)
		{
			d[i][j]=INF;
		}
		d[i][i]=0.0;
	}
 
	for(int i=0;i<w;i++)
	{
		int a,b;
 
		scanf("%d%d",&a,&b);
		a--;b--;
		road[a][b]=true;
		road[b][a]=true;
	}
	int flagcnt=0;
 
	for(int i=0;i<n;i++)
	{
		if(!vis[i]) dfs(i,flagcnt++);
	}
 
	for(int i=0;i<n;i++)
	{
		for(int j=i+1;j<n;j++)
		{
			dis[j][i]=dis[i][j]=DIS(i,j);
		}
	}
 
	for(int i=0;i<flagcnt;i++)
	{
		int icnt=Flag[i].cnt;
		d[i][i]=0;
		for(int j=i+1;j<flagcnt;j++)
		{
			int jcnt=Flag[j].cnt;
			double minx=INF;
 
			for(int k=0;k<icnt;k++)
			{
				for(int f=0;f<jcnt;f++)
				{
					minx=min(minx,dis[Flag[i].V[k]][Flag[j].V[f]]);
				}
			}
			if(minx<=m)
				d[j][i]=d[i][j]=minx;
			else
				d[j][i]=d[i][j]=INF;
		}
	}
 
	double ans=SPFA(sID,flagcnt);
 
	if(ans==INF)
		printf("-1\n");
	else
		printf("%d",(int)(ans*1000.0));
 
	return 0;
}
int haha=Main();
int main(){;}