#include<bits/stdc++.h>
using namespace std;
#define lalala ios_base::sync_with_stdio(false);cin.tie(NULL);
//#define endl "\n"
#define int long long int
#define pb push_back
signed main(){
lalala;
int n,m;cin>>n>>m;
int sa[n],sol[m];
for(int i=0;i<n;i++)cin>>sa[i];
for(int i=0;i<m;i++)cin>>sol[i];
sort(sa,sa+n);
sort(sol,sol+m);
if(n==m){
int mx=0;
for(int i=0;i<n;i++)mx=max(mx,abs(sa[i]-sol[i]));
cout<<mx<<endl;
return 0;
}
if(n<m){
int mn=0;
int l=0,r=m-n;
while(l<=r){
int mid=(l+r)/2;
int mx=0,mx2=-1,mx1=-1;
for(int i=mid;i<n+mid;i++){
mx=max(mx,abs(sa[i-mid]-sol[i]));
}
if(mid!=0){
for(int i=mid-1;i<n+mid-1;i++){
mx1=max(mx1,abs(sa[i-mid+1]-sol[i]));
}
}
if(mid!=m-n){
for(int i=mid+1;i<n+mid+1;i++){
mx2=max(mx2,abs(sa[i-mid-1]-sol[i]));
}
}
if(mx1==-1){
if(mx<=mx2){
l=mid;break;
}
else{
l=mid+1;
}
continue;
}
if(mx2==-1){
if(mx<=mx1){
l=mid;break;
}
else r=mid-1;
continue;
}
l=mid-1;r=mid+1;
if(mx1<mx)r=mid-1;
if(mx>mx2)l=mid+1;
}
for(int i=l;i<n+l;i++){
mn=max(mn,abs(sa[i-l]-sol[i]));
}
cout<<mn<<endl;
return 0;
}
int mn=0;
int l=0,r=n-m;
while(l<=r){
int mid=(l+r)/2;
int mx=0,mx2=-1,mx1=-1;
for(int i=mid;i<m+mid;i++){
mx=max(mx,abs(sa[i]-sol[i-mid]));
}
if(mid!=0){
for(int i=mid-1;i<m+mid-1;i++){
mx1=max(mx1,abs(sa[i]-sol[i-mid+1]));
}
}
if(mid!=n-m){
for(int i=mid+1;i<m+mid+1;i++){
mx2=max(mx2,abs(sa[i]-sol[i-mid-1]));
}
}
if(mx1==-1){
if(mx<=mx2){
l=mid;break;
}
else{
l=mid+1;
}
continue;
}
if(mx2==-1){
if(mx<=mx1){
l=mid;break;
}
else r=mid-1;
continue;
}
l=mid-1;r=mid+1;
if(mx1<mx)r=mid-1;
if(mx>mx2)l=mid+1;
}
for(int i=l;i<m+l;i++){
mn=max(mn,abs(sa[i]-sol[i-l]));
}
cout<<mn<<endl;
return 0;
}
