#include<iostream>
#include <cmath>
#include <algorithm>
using namespace std;
int a[100010],b[100010];
int main(){
	int m,n,sum=0,ans=0,mid,l,r;
	cin>>m>>n;
	for(int i=1;i<=m;i++){
		cin>>a[i];
	}
	for(int i=1;i<=n;i++){
		cin>>b[i];
	}
	
	for(int i=1;i<n;i++){
		ans=0;
		for(int j=1;j<=n-i;j++){
			if(a[j]>a[j+1]){
				sum=a[j];
				a[j]=a[j+1];
				a[j+1]=sum;
				ans++;
			}
		}
		if(ans==0) break;
	}
	ans=0;
	
	for(int i=1;i<=n;i++){
		l=0;
		r=n+1;
		while(l<r){
			mid=l+(r-l)/2;
			if(a[mid]<=b[i]) l=mid+1;
			if(a[mid]>b[i]) r=mid;
		}
//		if(a[l]-b[i]>a[l-1]-b[i]) ans+=a[l-1]-b[i];
//		else ans+=a[l]-b[i];
		ans+=min(abs(a[l-1]-b[i]),abs(a[l]-b[i]));
	}
	cout<<ans;
	return 0;
}