#include <cstdio>
#include <algorithm>
using namespace std; 
int main() {
	int m, n;
	long long ans = 0;
	int a[100005];
	int b[100005];
	scanf("%d %d", &m, &n);
	int x, y, e;
	for (int i = 0; i < m; ++i) {
		scanf("%d", &a[i]);
	}
	for (int i = 0; i < n; ++i) {
		scanf("%d", &b[i]);
	}
	sort(a, a + m);
	for (int i = 0; i < n; ++i) {
		e = lower_bound(a, a + m, b[i]) - a;
		if (e == m)
			ans += b[i] - a[e];
		else if (e == 0)
			ans += a[e] - b[i];
		else {
			x = a[e] - b[i];
			y = b[i] - a[e - 1];
			if (x > y)
				ans += y;
			else
				ans += x;
		}
	}
	printf("%lld", ans);
	return 0;
}