#include "railroad.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, int> pli;
#define debug(x) {cerr<<#x<<"="<<x<<"\n";}
#define debug2(x, y) {cerr<<#x<<", "<<#y<<" = "<<x<<", "<<y<<"\n";}
#define pb push_back
#define all(x) x.begin(), x.end()
const int inf=1000000010;
const ll INF=10000001000000000ll;
const int MAXN=400010;
int n, m, k;
int S[MAXN], T[MAXN], ps[MAXN];
int par[MAXN];
bool mark[MAXN];
vector<int> comp;
int getpar(int x){ return (par[x]==x?x:par[x]=getpar(par[x]));}
ll plan_roller_coaster(vector<int> s, vector<int> t){
n=s.size();
for (int i=1; i<=n; i++) S[i]=s[i-1], T[i]=t[i-1];
S[0]=inf;
T[0]=1;
for (int i=0; i<=n; i++){
comp.pb(T[i]);
comp.pb(S[i]);
}
sort(all(comp));
comp.resize(unique(all(comp))-comp.begin());
m=comp.size();
iota(par, par+m, 0);
for (int i=0; i<=n; i++){
S[i]=lower_bound(all(comp), S[i])-comp.begin();
T[i]=lower_bound(all(comp), T[i])-comp.begin();
par[getpar(S[i])]=getpar(T[i]);
ps[S[i]]++;
ps[T[i]]--;
}
for (int i=1; i<m; i++) ps[i]+=ps[i-1];
for (int i=0; i+1<m; i++) if (ps[i]){
if (ps[i]>0) return 1;
par[getpar(i)]=getpar(i+1);
}
for (int i=0; i<=n; i++) mark[getpar(S[i])]=1;
int ted=0;
for (int i=0; i<m; i++) ted+=mark[i];
if (ted==1) return 0;
return 1;
}
