#include <bits/stdc++.h>
#define int long long
using namespace std;
std::mt19937 rng(std::chrono::steady_clock::now().time_since_epoch().count());
const int MOD=1e9+7;
const int MX=1e6+7;
pair<int,int> seg[8*MX];//tudo pra
void update(int pos, int ini, int fim, int id, int val){
if(ini>id || fim<id)return;
if(ini==fim){
seg[pos]={val,ini};
return;
}
int e=2*pos,d=2*pos+1;
int m=(ini+fim)/2;
update(e,ini,m,id,val);
update(d,m+1,fim,id,val);
seg[pos]=min(seg[e],seg[d]);
}
pair<int,int> query(int pos, int ini, int fim, int l, int r){
if(ini>r || fim<l)return {MOD,MOD};
if(l<=ini && fim<=r)return seg[pos];
int e=2*pos,d=2*pos+1;
int m=(ini+fim)/2;
return min(query(e,ini,m,l,r),query(d,m+1,fim,l,r));
}
void solve() {
int n;cin>>n;
vector<array<int,2>> evs;//posicao,complementar
evs.reserve(2*n);
vector<vector<int>> adj(2*n+1);
vector<int> ls;
vector<pair<int,int>> q;
for(int i=1;i<=n;i++){
int l,r;cin>>l>>r;
ls.push_back(l);
q.push_back({l,r});
evs.push_back({l,r});
evs.push_back({r,l});
}
sort(evs.begin(),evs.end());
for(int i=1;i<=8*n;i++){
seg[i]={MOD,MOD};
}
for(auto [l,r]:evs){
if(l<r){
//botando o cara;
update(1,1,2*n,r,l);
auto [val,id]=query(1,1,2*n,l,r);
// cout<<l<<" "<<val<<"\n";
if(val<l){
adj[val].push_back(l);
adj[l].push_back(val);
}
}
else{
swap(l,r);
update(1,1,2*n,r,MOD);
}
}
int comp=0;
vector<int> color(2*n+1,-1);
auto bfs=[&](auto&& self,int node, int pai)->void{
for(auto a:adj[node]){
if(a==pai)continue;
color[a]=color[node]^1;
self(self,a,node);
}
// cout<<node<<" "<<pai<<"\n";
};
for(auto l: ls){
if(color[l]==-1){
color[l]=0;
bfs(bfs,l,l);
comp++;
}
}
stack<int> s[2];
for(auto [a,b]:evs){
if(a<b){
s[color[a]].push(a);
}
else{
if(s[color[b]].top()!=b){
cout<<0;return;
}
s[color[b]].pop();
}
}
int respat=1;
int potat=2;
for(int i=0;i<30;i++){
if(comp&(1<<i)){
respat*=potat;
respat%=MOD;
}
potat*=potat;
potat%=MOD;
}
cout<<respat;
}
int32_t main() {
std::cin.tie(0)->sync_with_stdio(0);
std::cin.exceptions(std::cin.failbit);
int T = 1;
// std::cin >> T;
while(T--) {
solve();
}
return 0;
}
