#include <bits/stdc++.h>
using namespace std;
using ll = long long;
long long min_total_length(vector<int> r, vector<int> b) {
vector<array<int, 2>> v;
for(auto x : r) v.push_back({x, -1});
for(auto x : b) v.push_back({x, 1});
sort(v.begin(), v.end());
int N = v.size();
vector<ll> dp(N+1, (ll)1e18), s(N+1, 0);
vector<int> lev(N+N+1, -1), R(3, 0), L(3, -1);
dp[0] = 0, lev[N] = 0;
for(int i=1, u=N;i<=N;i++) {
auto [x, y] = v[i-1];
u += y, s[i] = s[i-1] + x*y;
while(R[1-y] < N && (R[1-y] < i || v[R[1-y]][1] == y)) R[1-y]++;
if(R[1-y] < N) dp[i] = dp[i-1] + v[R[1-y]][0]-x;
if(L[1-y] != -1) dp[i] = min(dp[i], dp[i-1] + x-L[1-y]);
if(lev[u] != -1) dp[i] = min(dp[i], dp[lev[u]] + abs(s[i]-s[lev[u]]));
lev[u] = i, L[y+1] = x;
}
return dp[N];
}
