#include <bits/stdc++.h>
using namespace std;
long long m,n,sum=0;
long long a[100005],b[100005],bb[100005],u[100005];

void binarysearch(long long x,long long f)
{
	long long left=0,right=m-1;
	while(left<=right)
	{ long long mid=(left+right)/2;
		if(x==a[mid])
		{   
			bb[f]=a[mid];
			u[f]=0;
			return;
		}
		else if(x<a[mid])
		{
			right=mid-1;
		}
		else
		{
			left=mid+1;
		};
	}
	//cout<<left<<" "<<right<<endl;
	if(right==-1)
	{
		u[f]=a[0]-b[f];
		//cout<<u[f]<<endl;
	}
	if(left==m)
	{
		u[f]=a[m-1]-b[f];
	}
	else
	{
	
	for (long long j=right;j<=left;j++)
	{
		if (abs(a[j]-b[f])<u[f])
		{
		   u[f]=abs(a[j]-b[f]);
		   //cout<<u[f]<<endl;
		}
	}
}
	return;
}
int main ()
{   memset(u,9999999,sizeof(u));
    memset(bb,0,sizeof(bb));
	cin>>m>>n;
	for (int i=0;i<m;i++)
	  cin>>a[i];
	for (int i=1;i<=n;i++)
	{
		cin>>b[i];
	}
	sort(a,a+m);
	for (int i=1;i<=n;i++)
	{
		binarysearch(b[i],i);
	}
	
	for (int i=1;i<=n;i++)
	{  
		sum+=u[i];
	}
	cout<<sum;
}