tj

#include<iostream>
#include<cmath>
#include<algorithm>
#include<queue>
#include<stack>
#include<vector>
#include<cstdio>
#include<unordered_map>
#define ll long long
using namespace std;
ll ans;
int main() {
	ll n,m;
	cin>>n;
	cin>>m;
	vector<ll> v(n);
	for(ll i=0;i<n;i++) {
		ll tmp;
		scanf("%ld",&tmp);
		v[i]=tmp;
	}
	sort(v.begin(),v.end());
	while(m--) {
		ll tmp;
		scanf("%ld",&tmp);
		ll idx=lower_bound(v.begin(),v.end(),tmp)-v.begin();
//		cout<<"debug: "<<idx<<"\n";
		ans+=min(abs(tmp-v[idx-1]),min(abs(tmp-v[idx]),abs(v[idx+1]-tmp)));
	}
	cout<<ans;
}