#include <bits/stdc++.h>
#define int long long

using namespace std;

const int N = 1e5 + 10;
int a[N], b[N], n, m;
int ans = 0;
signed main() {
	cin >> m >> n;
	for (int i = 1; i <= m; i++) scanf("%d", &a[i]);
	for (int i = 1; i <= n; i++) scanf("%d", &b[i]);
	sort(a + 1, a + m + 1);
	for (int i = 1; i <= n; i++) {
		if (b[i] < a[1]) {
			ans += (a[1] - b[i]);
		} else if (b[i] > a[m]) {
			ans += (b[i] - a[m]);
		} else {
			int p = lower_bound(a + 1, a + m + 1, b[i]) - a;
			ans += min(abs(a[p - 1] - b[i]), abs(a[p] - b[i]));
		}
	}
	printf("%d", ans);
	return 0;
}