// ItnoE
#include<bits/stdc++.h>
#define x first
#define y second
using namespace std;
typedef long long ll;
const int N = 200005;
int P[N];
int Find(int v)
{
return (P[v] < 0 ? v : (P[v] = Find(P[v])));
}
inline bool Merge(int v, int u)
{
v = Find(v);
u = Find(u);
if (v == u)
return 0;
P[v] = u;
return 1;
}
int64_t plan_roller_coaster(vector < int > S, vector < int > T)
{
int n = (int)S.size();
vector < pair < int , pair < int , int > > > A, E;
for (int i = 0; i < n; i ++)
{
A.push_back({S[i], {1, i}});
A.push_back({T[i], {-1, i}});
}
A.push_back({(int)1e9, {1, n}});
A.push_back({1, {-1, n ++}});
sort(A.begin(), A.end());
int SM = 0;
ll tot = 0;
memset(P, -1, sizeof(P));
for (int i = 0; i + 1 < (int)A.size(); i ++)
{
SM += A[i].y.x;
tot += max(SM, 0) * (ll)(A[i + 1].x - A[i].x);
E.push_back({A[i + 1].x - A[i].x, {A[i].y.y, A[i + 1].y.y}});
if (A[i].x == A[i + 1].x || SM)
Merge(A[i].y.y, A[i + 1].y.y);
}
sort(E.begin(), E.end());
for (auto e : E)
if (Merge(e.y.x, e.y.y))
tot += e.x;
return (tot);
}
