#include <bits/stdc++.h>
#define N 5000+10
using namespace std;
int ans,l;
int main() {
	int m,n,a[N],b[N];
	cin>>m>>n;
	for(int i=1; i<=m; i++) {
		cin>>a[i];
	}
	for(int i=1; i<=n; i++)
		cin>>b[i];
	sort(a+1,a+m+1);
	for(int i=1; i<=n; i++) {
		l=0;
		int r=n+1;
		while(l<r) {
			int mid=(l+r)>>1;
			if(a[mid]<=b[i])
				l=mid+1;
			else
				r=mid;
		}
		if(b[i]<=a[1])
			ans+=a[1]-b[i];
		else
			ans+=min(abs(a[l-1]-b[i]),abs(a[l]-b[i]));
	}
	cout<<ans;
	return 0;
}