#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<algorithm>
#include<cmath>
#include<vector>
#include<set>
#include<map>
#include<stdlib.h>
#include<ctime>
#include<stack>
#include<queue>
using namespace std;
const int N=5e6+10;

int b[N],n,m,cnt,ans,a[N];

int main()
{
	cin>>n>>m;
	for(int i=1;i<=n;i++)
		cin>>a[i];
	sort(a+1,a+1+n);
	for(int i=1;i<=m;i++)
		cin>>b[i];
	for(int i=1;i<=m;i++){
		int l=1,r=n;
		while(l<r-1){
			int mid=(l+r)>>1;
			if(a[mid]<=b[i])
				l=mid;
			else
				r=mid;
		}
		if(abs(b[i]-a[l])<abs(b[i]-a[r]))
			cnt=abs(b[i]-a[l]);
		else cnt=abs(b[i]-a[r]);
		ans+=cnt;
	}
	cout<<ans; 
}