#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define debug(x) cerr << #x << " " << x << "\n"
#define debugs(x) cerr << #x << " " << x << " "
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef pair <ll, ll> pii;
typedef pair <long double, pii> muchie;
const ll NMAX = 2000001;
const ll VMAX = 21;
const ll INF = (1LL << 59);
const ll MOD = 1000000007;
const ll BLOCK = 318;
const ll base = 31;
const ll nr_of_bits = 21;
int aib[NMAX];
void update(int node, int x){
for(; node < NMAX; node += node&(-node))
aib[node] += x;
}
int query(int node){
if(!node)
return 0;
int sol = 0;
for(; node > 0; node -= node&(-node))
sol += aib[node];
return sol;
}
pii v[NMAX];
pii iesire[NMAX];
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int n, i, comp = 0;
cin >> n;
for(i = 1; i <= n; i++){
cin >> v[i].first >> v[i].second;
}
sort(v + 1, v + n + 1);
for(i = 1; i <= n; i++){
iesire[i] = {v[i].second, i};
}
sort(iesire + 1, iesire + n + 1);
for(i = 1; i <= n; i++){
update(v[i].second, 1);
int s = query(v[i].second - 1) - query(v[i].first);
if(s == 0){
comp++;
}
}
int rez = 1;
for(i = 1; i <= comp; i++){
rez *= 2;
rez %= MOD;
}
vector <int> a, b;
i = 1;
int j = 1;
while(i <= n && j <= n){
if(v[i].first < iesire[j].first){
if(!a.size() || v[a.back()].second >= v[i].second){
a.push_back(i);
}else if(!b.size() || v[b.back()].second >= v[i].second){
b.push_back(i);
}else{
rez = 0;
}
i++;
}else{
if((!a.size() || a.back() != iesire[j].second) && (!b.size() || b.back() != iesire[j].second)){
rez = 0;
}else{
if(a.size() && a.back() == iesire[j].second)
a.pop_back();
else
b.pop_back();
}
j++;
}
}
cout << rez;
return 0;
}
