#include<cstdio>#include<iostream>#include<queue>using namespace std;struct point{    long long x,y,num,counts,sets;}a[205];int cango[205][205] = {0},vis[205][205] = {0};int main(){    int n,m,k;    long long r;    cin >> n >> m >> k >> r;    for(int i = 1;i <= m+n;i++)    {       cin >> a[i].x >> a[i].y;       a[i].num = i;    }    for(int i = 1;i < m+n;i++)    {        for(int j = i;j <= m+n;j++)        {            if((a[i].x-a[j].x)*(a[i].x-a[j].x)+(a[i].y-a[j].y)*(a[i].y-a[j].y) <= r*r)            {                cango[i][j] = cango[j][i] = 1;            }        }    }    a[1].counts = 0;    a[1].sets = 0;    vis[1][0] = 1;    queue<point> q;    q.push(a[1]);    while(!q.empty())    {        long long num = q.front().num,counts = q.front().counts;        q.pop();        if(num == 2)        {            cout << counts-1 << endl;            return 0;        }        for(int i = 1;i <= m+n;i++)        {            long long sets;            if(i > n)    sets = q.front().sets+1;            else        sets = q.front().sets;            if(cango[num][i] && !vis[i][counts+1] && sets <= k)            {                a[i].sets = sets;                a[i].counts = counts+1;                q.push(a[i]);                vis[i][counts+1] = 1;            }        }    }}