#include "railroad.h"
#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T, typename U> using ordered_map = tree<T, U, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long ll;
typedef long double ld;
typedef double db;
typedef string str;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<pii> vpii;
typedef vector<pll> vpll;
typedef vector<str> vstr;
#define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
#define FORD(i,j,k,in) for(int i=(j); i >=(k);i-=in)
#define REP(i,b) FOR(i,0,b,1)
#define REPD(i,b) FORD(i,b,0,1)
#define pb push_back
#define mp make_pair
#define ff first
#define ss second
#define all(x) begin(x), end(x)
#define rsz resize
#define MANY_TESTS int tcase; cin >> tcase; while(tcase--)
const double EPS = 1e-9;
const int MOD = 1e9+7; // 998244353;
const ll INFF = 1e18;
const int INF = 1e9;
const ld PI = acos((ld)-1);
const vi dy = {1, 0, -1, 0, -1, 1, 1, -1};
const vi dx = {0, 1, 0, -1, -1, 1, -1, 1};
#ifdef DEBUG
#define DBG if(1)
#else
#define DBG if(0)
#endif
#define dbg(x) cout << "(" << #x << " : " << x << ")" << endl;
// ostreams
template <class T, class U>
ostream& operator<<(ostream& out, const pair<T, U> &par) {out << "[" << par.first << ";" << par.second << "]"; return out;}
template <class T>
ostream& operator<<(ostream& out, const set<T> &cont) { out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template <class T, class U>
ostream& operator<<(ostream& out, const map<T, U> &cont) {out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template<class T>
ostream& operator<<(ostream& out, const vector<T> &v){ out << "["; REP(i, v.size()) out << v[i] << ", "; out << "]"; return out;}
// istreams
template<class T>
istream& operator>>(istream& in, vector<T> &v){ for(auto &x : v) in >> x; return in; }
template<class T, class U>
istream& operator>>(istream& in, pair<T, U> &p){ in >> p.ff >> p.ss; return in; }
//searches
template<typename T, typename U>
T bsl(T lo, T hi, U f){ hi++; T mid; while(lo < hi){ mid = (lo + hi)/2; f(mid) ? hi = mid : lo = mid+1; } return lo; }
template<typename U>
double bsld(double lo, double hi, U f, double p = 1e-9){ int r = 3 + (int)log2((hi - lo)/p); double mid; while(r--){ mid = (lo + hi)/2; f(mid) ? hi = mid : lo = mid; } return (lo + hi)/2; }
template<typename T, typename U>
T bsh(T lo, T hi, U f){ lo--; T mid; while(lo < hi){ mid = (lo + hi + 1)/2; f(mid) ? lo = mid : hi = mid-1; } return lo; }
template<typename U>
double bshd(double lo, double hi, U f, double p = 1e-9){ int r = 3+(int)log2((hi - lo)/p); double mid; while(r--){ mid = (lo + hi)/2; f(mid) ? lo = mid : hi = mid; } return (lo + hi)/2; }
// some more utility functions
template<typename T>
pair<T, int> get_min(vector<T> &v){ typename vector<T> :: iterator it = min_element(v.begin(), v.end()); return mp(*it, it - v.begin());}
template<typename T>
pair<T, int> get_max(vector<T> &v){ typename vector<T> :: iterator it = max_element(v.begin(), v.end()); return mp(*it, it - v.begin());}
template<typename T> bool ckmin(T& a, const T& b){return b < a ? a = b , true : false;}
template<typename T> bool ckmax(T& a, const T& b){return b > a ? a = b, true : false;}
struct dsu{
vector<int> e;
dsu(){};
dsu(int n){
e.resize(n, -1);
}
int find(int x){ return (e[x] < 0 ? x : e[x] = find(e[x])); }
int size(int x){ return -e[find(x)]; }
int sameSet(int a, int b){ return find(a) == find(b); }
bool join(int a, int b){
a = find(a); b = find(b);
if(a == b) return false;
if(e[a] > e[b]) swap(a, b);
e[a] += e[b]; e[b] = a;
return true;
}
};
long long plan_roller_coaster(std::vector<int> s, std::vector<int> t) {
s.pb(INF); t.pb(0);
int n = (int) s.size();
vi vals;
REP(i, n){
vals.pb(s[i]);
vals.pb(t[i]);
}
sort(all(vals));
vals.erase(unique(all(vals)), vals.end());
vi in(2 * n, 0);
vi out(2 * n, 0);
dsu d(2 * n);
REP(i, n){
s[i] = lower_bound(all(vals), s[i]) - vals.begin();
t[i] = lower_bound(all(vals), t[i]) - vals.begin();
out[s[i]]++;
in[t[i]]++;
d.join(s[i], t[i]);
}
vector<array<int, 3>> edg;
ll ans = 0;
REPD(i, (int)vals.size() - 1){
if(i == 0) continue;
if(in[i] != out[i]){
d.join(i, i - 1);
if(in[i] > out[i]){
in[i - 1] += (in[i] - out[i]);
ans += (ll)(in[i] - out[i]) * (vals[i] - vals[i-1]);
}
else{
out[i - 1] += (out[i] - in[i]);
}
}
else{
edg.pb({vals[i] - vals[i-1], i, i -1});
}
}
sort(all(edg));
for(auto e : edg){
if(!d.sameSet(e[1], e[2])){
d.join(e[1], e[2]);
ans += e[0];
}
}
return ans;
}
