#include<bits/stdc++.h>
using namespace std;
#define int long long
const int N=200010,inf=1e9+7;
int n,m,a[N],b[N],ans=inf;
signed main()
{
	cin>>n>>m;
	for(int i=1;i<=n;i++)cin>>a[i];
	for(int i=1;i<=m;i++)cin>>b[i];
	sort(a+1,a+n+1);
	sort(b+1,b+m+1);
	int x=1,y=1;
	while(x<=n&&y<=m)
	{
		ans=min(ans,abs(a[x]-b[y]));
		if(a[x]>b[y])y++;
		else x++;
	}
	cout<<ans<<'\n';
	return 0;
}