#include <bits/stdc++.h>
#define all(x) (x).begin(),(x).end()
using namespace std;
using ll = long long;
//#define int ll
#define sz(x) ((int)(x).size())
using pii = pair<int,int>;
using tii = tuple<int,int,int>;
const int nmax = 5e5 + 5, inf = 1e9 + 5;
vector<tii> edg;
namespace DSU {
int dsu[nmax];
void init(int n) {
for(int i = 0; i <= n; i++)
dsu[i] = i;
}
int f(int x) { return x == dsu[x]? x: dsu[x] = f(dsu[x]); }
int cost(int a, int b, int w) {
a = f(a);
b = f(b);
if(a == b) return 0;
dsu[a] = b;
return w;
}
}
long long plan_roller_coaster(vector<int> s, vector<int> t) {
t.emplace_back(0);
s.emplace_back(inf);
unordered_map<int,int> nrm;
map<int,int> smen;
for(auto x : s)
smen[x]++;
for(auto x : t)
smen[x]--;
int edgc = 0;
int last = 0, cnt = 0;
ll cost = 0;
for(auto [a, b] : smen) {
nrm[a] = cnt++;
if(edgc == 0) {
//cerr << edgc << ' ' << a << ' ' << last << ' ' << cost << '+' << (a - last) * max(edgc, 0) << '\n';
edg.emplace_back(nrm[last], nrm[a], a - last);
}
else {
//cerr << edgc << ' ' << a << ' ' << last << ' ' << cost << '+' << (a - last) * max(edgc, 0) << '\t';
cost += (ll)(a - last) * max(edgc, 0);
//cerr << cost << '\n';
edg.emplace_back(nrm[last], nrm[a], 0);
}
edgc += b;
last = a;
}
for(int i = 0; i < sz(s); i++)
edg.emplace_back(nrm[s[i]], nrm[t[i]], 0);
DSU::init(sz(nrm));
sort(all(edg), [](auto a, auto b) { return get<2>(a) < get<2>(b); });
for(auto [x, y, w] : edg) {
//cerr << x << ' ' << y << ' ' << w << '\n';
cost += DSU::cost(x, y, w);
}
return cost;
}
