#include <bits/stdc++.h>
/// #pragma GCC optimize ("Ofast")
/// #pragma GCC target ("avx2")
/// #pragma GCC optimize("unroll-loops")
using namespace std;
using ll = long long;
using ii = pair<ll, ll>;
using vi = vector<int>;
#define ff first
#define ss second
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define lb lower_bound
const int MOD = 1000 * 1000 * 1000 + 7;
ll min_total_length(vector<int> R, vector<int> B) {
ll N = R.size(), M = B.size(), res = 0;
vector<pair<ll, ll>> A;
for(int l = 0; l < N; l++) A.pb(make_pair(R[l], 0));
for(int l = 0; l < M; l++) A.pb(make_pair(B[l], 1));
sort(A.begin(), A.end()); stack<ll> U, V;
for(int l = 0; l < N + M; l++) {
ii P = A[l];
if(P.ss == 1) {
if(V.empty()) {
U.push(A[l].ff);
continue;
}
res += ll(A[l].ff - V.top()); V.pop();
continue;
}
if(U.empty()) {
V.push(A[l].ff);
continue;
}
res += ll(A[l].ff - U.top()); U.pop();
}
while(!U.empty()) {
auto it = lb(R.begin(), R.end(), U.top());
ll ans = 1e18 + 7;
if(it != R.end()) ans = min(ans, abs(*it - U.top()));
if(it != R.begin()) it--, ans = min(ans, abs(*it - U.top()));
res += ans; U.pop();
}
while(!V.empty()) {
auto it = lb(B.begin(), B.end(), V.top());
ll ans = 1e18 + 7;
if(it != B.end()) ans = min(ans, abs(*it - V.top()));
if(it != B.begin()) it--, ans = min(ans, abs(*it - V.top()));
res += ans; V.pop();
}
return res;
}
