#include <bits/stdc++.h>
using namespace std;
int a[100100],b[100100];
int main(){
	int n,m;
	cin>>n>>m;
	for(int i=1;i<=n;i++)cin>>a[i];
	for(int i=1;i<=m;i++)cin>>b[i];
	sort(a+1,a+n+1);
	int ans=0;
	for(int i=1;i<=m;i++){
		int l=0,r=n+1;
		while(l<r){
			int mid=(l+r)/2;
			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;
}

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