#include<bits/stdc++.h>
using namespace std;
#define int long long
int school[100010],student[100010];
signed main(){
	int m,n,cnt=0;
	cin>>m>>n;
	for(int i=1;i<=m;i++)
	cin>>school[i];
	for(int i=1;i<=n;i++)
	cin>>student[i];
	sort(school+1,school+m+1);
	for(int i=1;i<=n;i++){
		int x=lower_bound(school+1,school+n+1,student[i])-school;
		if(x==1){
			cnt+=abs(school[1]-student[i]);
		}
		if(x==m+1){
	    	cnt+=abs(school[m]-student[i]);
		}
		else cnt+=min(abs(school[x]-student[i]),abs(school[x-1]-student[i]));
	}	
	cout<<cnt;
}