#include<iostream>
#include<cmath>
#include<algorithm>
using namespace std;
int main(){
	int m,n,a[10002],b[10002];
	cin>>m>>n;
	for(int i=0;i<m;i++){
		cin>>a[i];
	}
	for(int i=0;i<n;i++){
		cin>>b[i];
	}
	sort(a,a+m);
	int ans=0;
	for(int i=0;i<n;i++){
		int l=0,r=m-1,mid;
		int compare=abs(a[0]-b[i]);
		while(l<r){
			mid=l+(r-l)/2;
			if(abs(a[mid]-b[i])<compare){
				l=mid;
				compare=abs(a[mid]-b[i]);
			}
			else r=mid-1;
		}
		ans=ans+compare;
	}
	cout<<ans;
	return 0;
}