#include<bits/stdc++.h>
using namespace std;
#define ll long long
ll n,m,l,r,ans=0;
const ll N=1e8+5;
ll a[N],b[N];
ll find(ll g){
	l=1,r=n;
	while(l<=r){
		ll mid=(l+r)/2;
		if(a[mid]>=g){
			r=mid-1;
		}
		else{
			l=mid+1;
		}
	}
	return l;
}
int main(){
	cin>>n>>m;
	for(ll i=1;i<=n;i++){
		cin>>a[i];
	}
	sort(a+1,a+n+1);
	for(ll i=1;i<=m;i++){
		cin>>b[i];
		if(b[i]<=a[1]){
			ans+=a[1]-b[i];
		}
		else{
			ans+=min(abs(a[find(b[i])]-b[i]),abs(a[find(b[i])-1]-b[i]));
		}
	}
	cout<<ans;
	return 0;
}