#include<iostream>
#include<algorithm>
using namespace std;
int m,n,a[100010],q;
long long s;
int find(int x){
	int l=1,r=m,mid;
	while(l<=r){
		mid=(l+r)/2;
		if(x<a[mid])r=mid-1;
		else l=mid+1;
	}
	return r;
}
int main(){
	cin>>m>>n;
	for(int i=1;i<=m;i++)cin>>a[i];
	sort(a+1,a+n+1);
	for(int i=1;i<=n;i++){
		cin>>q;
		int k=find(q);
		if(q<=a[1]){
			s+=a[1]-q;
			continue;
		}
		if(q>=a[m]){
			s+=q-a[m];
			continue;
		}
		if(a[k+1]-q>=q-a[k]){
			s+=q-a[k];
		}
		else s+=a[k+1]-q;
	}
	cout<<s;
	return 0;
}