#include <bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define ar array
using namespace std;
typedef long long ll;
typedef pair<int, int> ii;
const int maxn = 2e5 + 5;
vector<int> seg[maxn];
vector<ll> last[maxn], first[maxn], f[maxn];
int N;
long long min_total_length(vector<int> r,vector<int> b) {
vector<ii> coor;
for (auto & it : r) {
coor.eb(it, 0);
}
for (auto & it : b) {
coor.eb(it, 1);
}
sort(coor.begin(), coor.end());
int now = -1;
seg[0].pb(-1e9);
for (auto & it : coor) {
if (it.se == now) {
seg[N].eb(it.fi);
} else {
++N;
seg[N].eb(-1e9);
seg[N].eb(it.fi);
now = it.se;
}
}
for (int i = 0; i <= N; ++i) {
int sz = seg[i].size();
last[i].assign(sz, 0);
first[i].assign(sz, 0);
f[i].assign(sz, 1e18);
for (int j = 1; j < sz; ++j) {
first[i][j] = first[i][j - 1] + seg[i][j];
last[i][j] = last[i][j - 1] + seg[i][sz - j];
}
}
f[0][0] = 0;
for (int i = 0; i < N; ++i) {
int nowsz = seg[i].size() - 1, nxtsz = seg[i + 1].size() - 1;
for (int j = nowsz; j > 0; --j) {
f[i][j - 1] = min(f[i][j - 1], f[i][j] + seg[i + 1][1] - seg[i][nowsz - j + 1]);
}
for (int j = 0; j <= min(nowsz, nxtsz); ++j) {
f[i + 1][nxtsz - j] = min(f[i + 1][nxtsz - j], f[i][j] + first[i + 1][j] - last[i][j]);
}
for (int j = nxtsz; j > 0; --j) {
if (i != 0)
f[i + 1][j - 1] = min(f[i + 1][j - 1], f[i + 1][j] + seg[i + 1][nxtsz - j + 1] - seg[i][nowsz]);
}
}
return f[N][0];
}
#ifdef LOCAL
signed main(void) {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#ifdef LOCAL
freopen("A.INP", "r", stdin);
freopen("A.OUT", "w", stdout);
#endif // LOCAL
int n, m; cin >> n >> m;
vector<int> r(n), b(m);
for (auto & it : r) cin >> it;
for (auto & it : b) cin >> it;
cout << min_total_length(r, b);
}
#endif
