#include <bits/stdc++.h>
#define int long long
using namespace std;
int n, m, ans;
int st[114514];
int sc[114514];
signed main()
{
	cin >> m >> n;
	for(int i = 1; i <= m; i = i + 1)
		cin >> sc[i];
	sort(sc + 1, sc + 1 + m);
	for(int i = 1; i <= n; i = i + 1)
		cin >> st[i];
	sort(st + 1, st + 1 + n);
	int l = 1;
	for(int i = 1; i <= n; i = i + 1)
	{
		while(abs(sc[l] - st[i]) > abs(sc[l + 1] - st[i]) && l < n)
			l ++;
		ans += abs(sc[l] - st[l]);
	}
	cout << ans << endl;
	return 0;
}