#include<bits/stdc++.h>
using namespace std;
int m,a[100005],n,b[100005],sum=0;
int main(){
	cin>>n>>m;	
	for(int i=1;i<=n;i++)cin>>a[i];
	for(int i=1;i<=m;i++)cin>>b[i];
	sort(a+1,a+n+1);
	for(int i=1;i<=m;i++){
		int l=1,r=n;
		while(l<r){
			int mid=(l+r+1)/2;
			if(a[mid]<=b[i]) l=mid;
			else r=mid-1;
		}
		if(abs(a[l]-b[i])>abs(a[l+1]-b[i])){
			sum=sum+abs(a[l+1]-b[i]);
		}
		else sum=sum+abs(a[l]-b[i]);
	}
	cout<<sum;
	return 0;