//什么时候我才能有杜爷一半强呀/kk
#include<cstdio>
#include<iostream>
#include<cstdlib>
#include<cmath>
#define int long long
const int N=114;
int n,m,x[N],y[N];
int read(){
	char ch=getchar();int nn=0,ssss=1;
	while(ch<'0'||ch>'9'){if(ch=='-')ssss*=-1;ch=getchar();}
	while(ch>='0'&&ch<='9'){nn=nn*10+(ch-'0');ch=getchar();}
	return nn*ssss;
}
long double sq(int x){return 1.*x*x;}
long double dis(int p1,int p2){return sq(x[p1]-x[p2])+sq(y[p1]-y[p2]);}
long double gd(int c){
	long double ret=0;
	for(int i=1;i<=c;i++){
		x[i]=read();y[i]=read();
		for(int j=1;j<i;j++)ret=std::max(ret,dis(i,j));
	}
	return ret;
}
signed main(){
	n=read();long double d1=gd(n);
	m=read();long double d2=gd(m);
	printf("%.10lf",sqrt(std::min(d1,d2)));
}