#include<bits/stdc++.h>
using namespace std;
int a[114514];
int main(){
	int n,m,b;
	cin>>n>>m;
	for(int i=1;i<=n;i++)cin>>a[i];
	sort(a+1,a+n+1);
	int sum=0;
	for(int i=1;i<=m;i++){
		cin>>b;
		int l=1,r=n,ans=0x7fffffff;
		while (r>l){
			int mid=l+(r-l)/2;
			if(a[mid]>=b){
				ans=min(ans,abs(b-a[mid]));
				r=mid;
			}else {
				ans=min(ans,abs(b-a[mid]));
				l=mid+1;
			}
		}
		sum+=ans;
	}
	cout<<sum;
}