#include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <deque>
#include <stack>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <cstring>
#include <cmath>
#include <cstdlib>
#include <algorithm>
#include <random>
#include <iomanip>
#include <functional>
#include <cassert>
using namespace std;
typedef long long ll;
#include "wiring.h"
const ll Inf = 1e18;
long long min_total_length(vector <int> r, vector <int> b) {
int n = r.size();
int m = b.size();
vector <pair <int, int>> gs;
for (int i = 0; i < n; ++i) {
gs.push_back({r[i], 0});
}
for (int i = 0; i < m; ++i) {
gs.push_back({b[i], 1});
}
sort(gs.begin(), gs.end());
int k = gs.size();
vector <int> g_sz;
for (int i = 0; i < k; ++i) {
int uk = i;
while (uk < k && gs[i].second == gs[uk].second) {
++uk;
}
g_sz.push_back(uk - i);
i = uk - 1;
}
int cnt = g_sz.size();
vector <int> where(k);
{
int uk = 0;
for (int i = 0; i < cnt; ++i) {
for (int j = uk; j < uk + g_sz[i]; ++j) {
where[j] = i;
}
uk += g_sz[i];
}
}
vector <int> ps(cnt);
for (int i = 0; i < cnt; ++i) {
if (i > 0) ps[i] += ps[i - 1];
ps[i] += g_sz[i];
}
vector <ll> pref(k + 1);
for (int i = 0; i < k; ++i) {
pref[i + 1] = pref[i] + gs[i].first;
}
vector <ll> dp(k + 1, Inf);
dp[0] = 0;
for (int i = 1; i <= k; ++i) {
int id = where[i - 1];
if (id > 0) {
dp[i] = min(dp[i], dp[i - 1] + abs(gs[i - 1].first - gs[ps[id - 1] - 1].first));
}
if (id + 1 < cnt) {
dp[i] = min(dp[i], dp[i - 1] + abs(gs[i - 1].first - gs[ps[id]].first));
}
if (id + 1 < cnt) {
int have_free = ps[id] - i + 1;
if (g_sz[id + 1] >= have_free) {
ll delta = 0;
delta += pref[ps[id] + have_free] - pref[ps[id]];
delta -= pref[i - 1 + have_free] - pref[i - 1];
/*for (int j = 0; j < have_free; ++j) {
delta += abs(gs[i - 1 + j].first - gs[ps[id] + j].first);
}*/
dp[ps[id] + have_free] = min(dp[ps[id] + have_free], dp[i - 1] + delta);
}
}
}
return dp[k];
}
#ifdef LOCAL
int main() {
ios_base::sync_with_stdio(false); cin.tie(0);
#ifdef LOCAL
freopen("input.txt", "r", stdin);
#endif
int n, m;
cin >> n >> m;
vector<int> r(n), b(m);
for(int i = 0; i < n; i++)
cin >> r[i];
for(int i = 0; i < m; i++)
cin >> b[i];
long long res = min_total_length(r, b);
cout << res << '\n';
}
#endif
