#include<bits/stdc++.h>
using namespace std;
int m, n, a[100010], b[100010], res = 0;

int main()
{
	cin >> m >> n;
	for(int i=0; i<m; i++)
	{
		cin >> a[i];
	}
	for(int i=0; i<n; i++)
	{
		cin >> b[i];
	}
	sort(a + 0, a + m);
	for(int i=0; i<n; i++)
	{
		int l = 0, r = m - 1, ans = 1e6 + 10;
		while(l < r)
		{
			int mid = (l + r) / 2;
			if(a[mid] >= b[i]) ans = min(ans, abs(b[i] - a[mid])), r = mid;
			else l = mid + 1, ans = min(ans, abs(b[i] - a[mid]));
		}
		res += ans;
	}
	printf("%d", res);
	return 0;
}