#include<bits/stdc++.h>
using namespace std;
long long a[100010],b[100010];
int main(){
	int n,m;
	cin>>n>>m;
	for(int i=1;i<=n;i++){
		cin>>a[i];
	}
	sort(a+1,a+1+n);
	for(int i=1;i<=m;i++){
		cin>>b[i];
	}
	int js=0;
	for(int i=1;i<=m;i++){
		int l=1,r=n;
		while(l<=r){
			int mid=l+(r-l)/2;
			if(a[mid]<=b[i]){
				l=mid+1;
			}
			else{
				r=mid-1;
			}
		}
		if(b[i]<=a[1]){
			js+=a[1]-b[i];
		}
		else{
			js+=min(abs(a[l]-b[i]),abs(a[l-1]-b[i]));
		}
	}
	cout<<js;
}

#1没过