#include <iostream>
#include <iomanip>
#include <vector>
#include <cmath>
#include <algorithm>
#include <set>
#include <queue>
#include <map>
#include <unordered_map>
#include <stack>
#include <bit>
#include <bitset>
#include <string>
#include <cstring>
#include <iterator>
#include <random>
#define ll long long
#define ld long double
#define inf (ll)(2*1e18)
#define sort(a) sort(a.begin(), a.end())
#define reverse(a) reverse(a.begin(), a.end())
#define pb push_back
#define endl "\n"
using namespace std;
ll mod=1e9+7;
ll binPow(ll a, ll n){
ll res = 1, b=a;
while(n){
if(n&1){
res *= b;
res %= mod;
--n;
}
b *= b;
b %= mod;
n /= 2;
}
return res;
}
void solve(){
ll n, i, l, r, cnt=0, id, x;
cin>>n;
vector<pair<ll, ll>> add(2*n);
vector<ll> a(n);
vector<ll> b(n);
set<ll> s;
for(i=0;i<n;++i){
cin>>l>>r;
--l;
--r;
add[l] = {r, i};
add[r] = {l, i};
}
for(i=0;i<2*n;++i){
x = add[i].first;
id = add[i].second;
if(i < x){
s.insert(x);
auto it = s.find(x);
if(it == s.begin()){
++cnt;
a[id] = -inf;
}else{
--it;
a[id] = *it;
}
}else{
s.erase(i);
}
}
for(i=2*n-1;i>=0;--i){
x = add[i].first;
id = add[i].second;
if(i > x){
s.insert(x);
auto it = s.find(x);
++it;
if(it == s.end()){
b[id] = inf;
}else{
b[id] = *it;
}
}else{
s.erase(i);
}
}
for(i=0;i<n;++i){
if(a[i] > b[i]){
cout<<0<<endl;
return;
}
}
cout<<binPow(2, cnt)<<endl;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
srand(time(nullptr));
ll t=1;
// cin>>t;
for(;t>0;--t){
solve();
}
return 0;
}
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