#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
bool cmp(int x,int y){
	return x<y;
}
int main(){
	ll m,n;
	cin>>m>>n;
	ll a[100001],b[100001];
	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,cmp);
	long long  ans=0;
	for(int i=1;i<=n;i++){
		if(b[i]<=a[1]){
			ans+=a[1]-b[i];
			continue;
		}
		if(b[i]>=a[m]){
			ans+=b[i]-a[m];
			continue;
		}
		ll l=1,r=m+1,minn=10000001;
		while(l+1<r){
			ll mid=(l+r)/2;
			ll c=b[i]-a[mid];
			minn=min(minn,abs(c));
			if(c<=0)r=mid;
			else l=mid;
		}
		ans+=minn;
	}
	cout<<ans;

}