#include<iostream>
#include<cmath>
#include<cstring>
#include<algorithm>
using namespace std;
int m,n;
long long int answer=0,lest=0x3f3f3f3f;
long long int school[1001000],student[1001000];
int main()
{
	//freopen("dream.in","r",stdin);
	//freopen("dream.out","w",stdout);
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	cin>>m>>n;
	for (long long int i=1;i<=m;i++)
	{
		cin>>school[i];
	}
	sort(school+1,school+1+m);
	for (long long int i=1;i<=n;i++)
	{
		cin>>student[i];
	}
	for (long long int i=1;i<=n;i++)
	{
		if (student[i]<=school[1])
		{
			answer+=school[1]-student[i];
			continue;
		}
		if (student[i]>=school[m])
		{
			answer+=school[m]-student[i];
			continue;
		}
		long long int left=1,right=m,middle;
		while (left<right-1)
		{
			middle=(left+right)/2;
			if (school[middle]>student[i]) right=middle;
			else left=middle;
		}
		lest=min(student[i]-school[left],school[right]-student[i]);
		answer+=lest;
	}
	cout<<answer;
	//fclose(stdin);
	//fclose(stdout);
	return 0;
	
}