#include <bits/stdc++.h>
using namespace std;
struct DLX
{const static int maxn=64,maxm=64,maxnode=maxn*maxn;int n,m,sz,anssz;int u[maxnode],d[maxnode],l[maxnode],r[maxnode],row[maxnode],col[maxnode];//row col 记录该节点i坐标int h[maxn],colcnt[maxm];void init(int _n,int _m) //数据位于1,1...n,m
    {n=_n,m=_m;for(int i=0;i<=m;i++)//1..m是每一列的辅助结点 0代表(0,0)即head
        {u[i]=d[i]=i;l[i]=i-1;r[i]=i+1;col[i]=i;row[i]=0;colcnt[i]=0;}l[0]=m;r[m]=0;sz=m;anssz=INT_MAX;for(int i=1;i<=n;i++)h[i]=-1;}void push(int x,int y){colcnt[y]++;col[++sz]=y;row[sz]=x;d[sz]=d[y]; //加入列首元素后面u[sz]=y;u[d[y]]=sz;d[y]=sz;if(h[x]<0) h[x]=r[sz]=l[sz]=sz; //成为行首元素else{int hd=h[x]; //加入行首节点右边l[sz]=hd;r[sz]=r[hd];l[r[hd]]=sz;r[hd]=sz;}}void repeat_remove(int x){for(int i=d[x];i!=x;i=d[i])l[r[i]]=l[i],r[l[i]]=r[i];}void repeat_resume(int x){for(int i=u[x];i!=x;i=u[i])l[r[i]]=r[l[i]]=i;}int H(){static bool vis[maxm];memset(vis,0,sizeof vis);int res=0;for(int i=r[0];i!=0;i=r[i]){ //如果该列未被标标记,则标记该列中每行的列if(vis[i]) continue;res++;vis[i]=1;for(int j=d[i];j!=i;j=d[j])for(int k=r[j];k!=j;k=r[k]) vis[col[k]]=1;}return res;//易证res <= ans-dep
    }void repeat_dance(int dep){if(r[0]==0){anssz=min(anssz,dep); return ;}if(dep+H()>=anssz) return ;int cur=r[0];for(int i=r[0];i!=0;i=r[i]) if(colcnt[i]<colcnt[cur])cur=i;
//        repeat_remove(cur);for(int i=d[cur];i!=cur;i=d[i]){repeat_remove(i);for(int j=r[i];j!=i;j=r[j]) repeat_remove(j);repeat_dance(dep+1);for(int j=l[i];j!=i;j=l[j]) repeat_resume(j);repeat_resume(i);}
//        repeat_resume(cur);
    }
};
DLX dlx;
struct point{double x,y;double dis(const point &a){return hypot(a.x-x,a.y-y);}
};
point city[64],radar[64];
bool le(double a,double b)
{if(a<b)return true;
}
int main()
{
#ifdef shuaishuaifreopen("in.txt","r",stdin);
#endif // shuaishuai
//二分裸重复覆盖int t;scanf("%d",&t);while(t--){int n,m,k;scanf("%d%d%d",&n,&m,&k);for(int i=0;i<n;i++)scanf("%lf%lf",&city[i].x,&city[i].y);for(int i=0;i<m;i++)scanf("%lf%lf",&radar[i].x,&radar[i].y);double l=0,r=2000;do{double mi=(l+r)/2;static bool vis[64];memset(vis,0,sizeof vis);int cnt=0;dlx.init(m,n);for(int i=0;i<m;i++)for(int j=0;j<n;j++)if(radar[i].dis(city[j])<=mi){if(!vis[j]) vis[j]=true,cnt++;dlx.push(i+1,j+1);}if(cnt!=n) {l=mi;continue;}dlx.repeat_dance(0);if(dlx.anssz>k) l=mi;else r=mi;}while(r-l>1e-7);printf("%.6f\n",(l+r)/2);}return 0;
}