#include<iostream>
#include<cstdio> 
#include<iomanip>
#include<algorithm>
using namespace std;
long long m,n,a[100005],b[100005],l,r,s,q;
int main()
{
	cin>>m>>n;
	for(int i=1;i<=m;i++)
	cin>>a[i];
	sort(a+1,a+m);
	for(int i=1;i<=n;i++)
	{
		cin>>b[i];
		l=1;
		r=m;
		while(l<r){
			int mid=(l+r)>>1;
			if(a[mid]>=b[i])r=mid;
			else l=mid+1;
		}
		q=a[l];
		l=1;
		r=m;
		while(l<r){
			int mid=(l+r+1)>>1;
			if(a[mid]<=b[i])l=mid;
			else r=mid-1;
		}
		s+=min(abs(b[i]-q),abs(b[i]-a[l]));
	}
	cout<<s;
	
	return 0;
}