#include<cstdio>

#include<iostream>

#include<queue>

using namespace std;

struct point{

    long long x,y,num,counts,sets;

}a[];

int cango[][] = {},vis[][] = {};

int main()

{

    int n,m,k;

    long long r;

    cin >> n >> m >> k >> r;

    for(int i = ;i <= m+n;i++)

    {

       cin >> a[i].x >> a[i].y;

       a[i].num = i;

    }

    for(int i = ;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] = ;

            }

        }

    }

    a[].counts = ;

    a[].sets = ;

    vis[][] = ;

    queue<point> q;

    q.push(a[]);

    while(!q.empty())

    {

        long long num = q.front().num,counts = q.front().counts;

        q.pop();

        if(num == )

        {

            cout << counts- << endl;

            return ;

        }

        for(int i = ;i <= m+n;i++)

        {

            long long sets;

            if(i > n)    sets = q.front().sets+;

            else        sets = q.front().sets;

            if(cango[num][i] && !vis[i][counts+] && sets <= k)

            {

                a[i].sets = sets;

                a[i].counts = counts+;

                q.push(a[i]);

                vis[i][counts+] = ;

            }

        }

    }

}