using namespace std;
int a[100010];// b[100010];
int main(){
	freopen("exam.in", "r", stdin);
    freopen("exam.out", "w", stdout);
	int n, m;
	cin >> n >> m;
	for(int i = 0; i < n; i ++){
		cin >> a[i];
	}
	sort(a, a + n);
	int sum = 0;
	for(int i = 0; i < m; i ++){
		int t;
		cin >> t;
		if(t <= a[0]){
			sum += abs(a[0] - t);
		}
		else if(t >= a[n-1]){
			sum += abs(a[n-1] - t);
		}
		else{
			if(a[lower_bound(a, a+n, t) - a] - t < t - a[lower_bound(a, a+n, t) - a - 1]){
				sum += abs(a[lower_bound(a, a+n, t) - a] - t);
			}
			else{
				sum += abs(a[lower_bound(a, a+n, t) - a - 1] - t);
			}
		}
	}
	cout << sum;
}