/*DavitMarg*/
#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <string>
#include <cstring>
#include <map>
#include <set>
#include <queue>
#include <iomanip>
#include <bitset>
#include <stack>
#include <cassert>
#include <iterator>
#include <ctype.h>
#include <fstream>
#define mod 1000000007ll
#define LL long long
#define LD long double
#define MP make_pair
#define PB push_back
#define all(v) v.begin(),v.end()
using namespace std;
struct yaxq
{
int a, b, i;
yaxq(int A=0,int B=0,int I=0)
{
a = A;
b = B;
i = I;
}
};
bool operator<(yaxq p, yaxq q)
{
if(p.a!=q.a)
return p.a < q.a;
return p.b < q.b;
}
int n,k;
pair<int, int> t[4 * 300005];
yaxq a[300005];
vector<yaxq> s,ans,ans2;
void build(int v, int l, int r)
{
if (l == r)
{
t[v] = MP(s[l].b, l);
return;
}
int m = (l + r) >> 1;
build(v * 2, l, m);
build(v * 2 + 1, m + 1, r);
t[v] = max(t[v * 2], t[v * 2 + 1]);
}
void update(int v,int l,int r,int pos,int val)
{
if (l == r)
{
t[v].first = val;
return;
}
int m = (l + r) >> 1;
if (pos <= m)
update(v * 2, l, m, pos, val);
else
update(v * 2 + 1, m + 1, r, pos, val);
t[v] = max(t[v * 2], t[v * 2 + 1]);
}
pair<int, int> get(int v,int l,int r,int i,int j)
{
if (i > j)
return MP(-mod, -1);
if (l == i && r == j)
return t[v];
int m = (l + r) >> 1;
return max(
get(v * 2, l, m, i, min(j, m)),
get(v * 2 + 1, m + 1, r, max(m + 1, i), j)
);
}
int Main()
{
for (int i = 1; i <= n; i++)
s.PB(a[i]);
ans.PB(yaxq(-mod, mod, 0));
if (!s.empty())
{
sort(all(s));
build(1, 0, s.size() - 1);
while (1)
{
int l, r, m, pos = -1;
l = 0;
r = s.size() - 1;
while (l <= r)
{
m = (l + r) >> 1;
if (s[m].a <= ans.back().b)
{
pos = m;
l = m + 1;
}
else
r = m - 1;
}
if (pos == -1)
break;
pair<int, int> nxt = get(1, 0, s.size() - 1, 0, pos);
if (nxt.first == -mod)
break;
ans.PB(s[nxt.second]);
update(1, 0, s.size() - 1, nxt.second, -mod);
}
}
return 0;
}
LL plan_roller_coaster(vector<int> S, vector<int> T)
{
n = S.size();
for (int i = 1; i <= n; i++)
a[i] = yaxq(-S[i-1],-T[i-1],i);
Main();
return !(ans.size()-1==s.size());
}
#ifdef death
int main()
{
int N;
vector<int> S, T;
cin >> N;
for (int i = 0; i < N; i++)
{
S.PB(0);
cin >> S.back();
T.PB(0);
cin >> T.back();
}
cout << plan_roller_coaster(S, T) << endl;
return 0;
}
#endif
/*
*/
