#include<bits/stdc++.h>
#define ll long long
using namespace std;
ll m,n;
ll sch[100010],stu[100010];
ll sum;
int main()
{
	cin>>m>>n;
	for(ll i=0;i<m;i++)
	{
		cin>>sch[i];
	}
	for(ll i=0;i<n;i++)
	{
		cin>>stu[i];
	}
	sort(sch,sch+m);
	for(ll i=0;i<n;i++)
	{
		ll index=lower_bound(sch,sch+m,stu[i])-sch;
		if(index==0)
		{
			sum+=sch[0]-stu[i];
			continue;
		}
		sum+=min(sch[index]-stu[i],stu[i]-sch[index-1]);
	}
	cout<<sum;
	return 0;
}