#include "railroad.h"
#include <vector>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <map>
#include <unordered_map>

#define X first
#define Y second
#define PB push_back

using namespace std;

typedef vector < int > vi;
typedef long long ll;
typedef pair < int , int > pii;
typedef vector < pii > vp;

const int INF = 0x3f3f3f3f;
const int N = 4e5 + 500;

bool cmp(pii A, pii B){
    if(A.X - A.Y == B.X - B.Y) return A.X < A.Y;
    return A.X - A.Y > B.X - B.Y;
}

int n, m;
vector < int > v;
vector < pii > e;
unordered_map < int , int > deg, par, out;

int pr(int x){
    if(!par[x]) return par[x] = x;
    if(x == par[x]) return x;
    return par[x] = pr(par[x]);
}

void mrg(int x,int y){
    par[pr(x)] = pr(y);
}

ll plan_roller_coaster(vi s, vi t) {
    n = s.size();
    for(int i = 0;i < n;i++){
        deg[s[i]]++; deg[t[i]]--;
        v.PB(s[i]), v.PB(t[i]);
        mrg(s[i], t[i]);
    }
    sort(v.begin(), v.end());
    v.erase(unique(v.begin(), v.end()), v.end());
    n = (int)v.size();
    ll sol = 0;
    for(int i = 0;i < n;i++){
        out[v[i]] = out[v[i - 1]] - deg[v[i]] + (i == 0) - (i == n - 1);
        if(out[v[i]] < 0 && i != n - 1){
            mrg(v[i], v[i + 1]);
            sol -= (ll)(v[i + 1] - v[i]) * out[v[i]];
        }
        if(out[v[i]] == 0 && i != n - 1){
            e.PB({v[i], v[i + 1]});
        }
        if(out[v[i]] > 0 && i != n - 1){
            mrg(v[i], v[i + 1]);
        }
        //printf("OUT %d je %d\n:", v[i], out[v[i]]);
    }
    //printf("SOL   = %lld\n", sol);
    sort(e.begin(), e.end(), cmp);
    for(int i = 0;i < e.size();i++){
        if(pr(e[i].X) != pr(e[i].Y)){
            mrg(e[i].X, e[i].Y);
            sol += e[i].Y - e[i].X;
        }
    }
    return sol;
}