#include<bits/stdc++.h>
using namespace std;
const int large = 100000 + 10;
int m, n, x;
vector<int> sor;
int stu[large];
long long ans;

int main() {
//	freopen("P1678_1.in", "r", stdin);
//  freopen(".out", "w", stdout);
	ios::sync_with_stdio(false);
	cin.tie(0), cout.tie(0);
	cin >> m >> n;
	for (int i = 1; i <= m; i++) cin >> x, sor.push_back(x);
	for (int i = 1; i <= n; i++) cin >> x, stu[i] = x;
	sort(sor.begin(), sor.end());
	for (int i = 1; i <= n; i++) {
		int pos = upper_bound(sor.begin(), sor.end(), stu[i]) - sor.begin();
		ans += min(abs(sor[pos] - stu[i]), abs(sor[pos - 1] - stu[i]));
	}
	cout << ans;
	return 0;
}

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