#include<iostream>
#include<algorithm>
#include<cmath>
using namespace std;
const int N = 1e6 + 10;
int a[N],b[N],c[N];
int main()
{
	int m,n,j = 0;
	long long sum = 0;
	cin >> m >>n;
	int d = n;
	for(int i = 0;i < m;i ++)
	cin >> a[i];
	for(int i = 0;i < n;i ++)
	cin >> b[i];
	sort(a,a + m);
	while(n --)
	{
		int l = 0, r = m - 1;
		while(l <= r)
		{
			int mid = l + r + 1 >> 1;
			if(b[j] < a[0])
			{
				c[j++] = a[0];
				break;
			
			}
			 if(b[j]> a[m-1])
			{
				c[j++] = a[m - 1];
				break;
			}
			if(b[j] >= a[mid]) l = mid + 1;
			else
			r = mid - 1;
			 if(a[l] >= b[j] && a[l - 1] <= b[j])
			{
			if(abs(b[j]- a[l]) > abs(b[j]- a[l - 1]))
			c[j++] = a[l - 1];
			else
			c[j++] = a[l];
			break;	
			}
		
		}
	}
		for(int i = 0;i < d;i++)
			{   
				sum += abs(b[i] - c[i]);
			}
			cout << sum;
			return 0;
 }