#include <iostream>
#include <cstdio> 
#include <algorithm>
using namespace std;

const int N = 100010;
const int M = 100010;
int stu[N], sch[M];
int n, m;
long long mi;

int main(){
	mi = 0;
	scanf("%d%d", &m, &n);
	for(int i = 0; i < m; i ++)	scanf("%d", &sch[i]);
	sort(sch, sch+m);
	for(int i = 0; i < n; i ++)	scanf("%d", &stu[i]);
	
	
	for(int i = 0; i < n; i ++){
		int ans = 10000;
		int l = 0, r = m - 1;
		while(l < r){
			int mid = l + (r - l) / 2;
			if(sch[mid] >= stu[i]){
				ans = min(ans, abs(sch[mid] - stu[i]));
				r = mid;
			}
			else{
				ans = min(ans, abs(sch[mid] - stu[i]));
				l = mid + 1;
			}
		}
		mi += ans;
		
	}
	
	cout<<mi<<endl;
	return 0;
}