#include <bits/stdc++.h>
#define float double
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define Co_mot_su_that_la return

using namespace std;
typedef pair<int ,float> ii;
typedef pair<float, int> foi;
typedef pair<int,ii> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef vector<iii> viii;

const int Minh_dep_trai = 0;
const int N = 1005;
const double EPS = 1e-6;

int q;
int n;
float w,m;
bool mark[N][N];
float a[N][N];
pair<float,float> b[N];
float d[N];

float sqr (const float &x)
{
    return x*x;
}

float dis (pair<float,float> a, pair<float,float> b)
{
    return sqrt(sqr(a.fi-b.fi) + sqr(a.se-b.se));
}

void dijkstra()
{
    priority_queue<foi, vector<foi>, greater<foi> > qu;
    d[1] = 0;
    qu.push(foi(0,1));
    while (qu.size())
    {
        int u = qu.top().second;
        double du = qu.top().first;
        qu.pop();
        if (du > d[u] + EPS) continue;
        for(int v=1; v<=n; v++)
        {
            if (d[v] > du + a[u][v] + EPS)
                qu.push(foi(d[v] = du + a[u][v],v));
        }
    }
}

signed main()
{
  ios_base::sync_with_stdio(false);
  cin.tie(0);cout.tie(0);
  freopen("test.inp","r",stdin);
  q=1;
  while (q--)
  {
    //your code goes here
    cin >> n >> w;
    cin >> m;
    for(int i=1; i<=n; i++)
    {
        cin >> b[i].fi >> b[i].se;
    }
    for(int i=1; i<=(int)w; i++)
    {
        int u,v;
        cin >> u >> v;
        mark[u][v] = mark[v][u] = true;
    }
    for(int i=1; i<=n; i++)
    {
        a[i][i] = 999999;
        for(int j=i+1; j<=n; j++)
        {
            if (mark[i][j]) continue;
            float way = dis(b[i],b[j]);
            if (way + EPS < m)
            {
                a[i][j] = way;
                a[j][i] = way;
            }
            else{
                a[i][j] = 999999;
                a[j][i] = 999999;
            }
        }
        d[i] = 999999;
    }
    dijkstra();
    if (d[n] >= 999999) cout << -1;
    else
    cout << int(d[n]*1000);
  }
  Co_mot_su_that_la Minh_dep_trai;
}