#include <bits/stdc++.h>
using namespace std;
int m,n,num,ans,sch[100001];
int main(){
	cin>>m>>n;
	for (int i=1;i<=m;++i) cin>>sch[i];
	sort(sch+1,sch+m+1);
	for (int i=1;i<=n;++i){
		int l=1,r=m,ls=1000001;
		cin>>num;
		while (l<=r){
			int mid=(l+r)/2;
			if (sch[mid]==num){
				ls=0;
				break;
			}
			else if(sch[mid]>num){
				ls=min(ls,sch[mid]-num);
				r=mid-1;
			}
			else{
				ls=min(ls,num-sch[mid]);
				l=mid+1;
			}
		}
		ans+=ls;
	}
	cout<<ans;
	return 0;
}

WA on #11