#include<bits/stdc++.h>
using namespace std;
int a[100001],b[100001];
int main(){
	int n,m;
	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);
	int ans=0;
	for(int i=1;i<=m;i++){
		int start=1,end=n+1;
		int mid=(start+end)/2;
		while(start<end){
			if(a[mid]<=b[i]){
				start=mid+1;
			}
			else end=mid;
		}
		if(b[i]<=a[1]){
			ans+=a[1]-b[i];
		}
		else{
			ans+=min(abs(a[start-1]-b[i]),abs(a[start]-b[i]));
		}
	}
	cout<<ans;
	return 0;
}