#include <bits/stdc++.h>
#define ll long long
#define str string
#define ins insert
#define ld long double
#define pb push_back
#define pf push_front
#define pof pop_front()
#define pob pop_back()
#define lb lower_bound
#define ub upper_bound
#define endl "\n"
#define fr first
#define sc second
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define sz size()
#define bc back()
#define ar array
#define vll vector<ll>
using namespace std;/*
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;*/
template <class _T>
bool chmin(_T &x, const _T &y){
if(x>y){
x=y;
return true;
}
return false;
}
template <class _T>
bool chmax(_T &x, const _T &y){
bool flag=false;
if (x<y){
x=y;flag|=true;
}
return flag;
}
//#define ordered_set tree<ll, null_type,less_equal<ll>, rb_tree_tag,tree_order_statistics_node_update>
void fre(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
void start(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
}
const ll inf=2e18+7;
const ll mod=1e9+7;
const ll N=2e6+7;
struct st{
ll t[N*4];
st(){
for(ll i=0;i<N*4;i++)t[i]=-inf;
}
void upd(ll pos,ll val,ll v=1,ll tl=1,ll tr=N){
if(tl>pos || tr<pos)return;
if(tl==tr){
t[v]=val;
return;
}
ll tm=(tl+tr)/2;
upd(pos,val,v*2,tl,tm);
upd(pos,val,v*2+1,tm+1,tr);
t[v]=max(t[v*2],t[v*2+1]);
}
ll get(ll l,ll r,ll v=1,ll tl=1,ll tr=N){
if(tl>r || tr<l)return -inf;
if(l<=tl && tr<=r)return t[v];
ll tm=(tl+tr)/2;
return max(get(l,r,v*2,tl,tm),get(l,r,v*2+1,tm+1,tr));
}
}mx,mn;
ll vis[N];
ll id[N];
ll a[N],b[N];
ll type[N];
vll vt[2];
void dfs(ll v){
vis[v]++;
mx.upd(a[v],-inf);
mn.upd(b[v],-inf);
vt[type[v]].pb(v);
while(true){
ll i=mx.get(a[v],b[v]);
if(b[v]<i){
type[id[i]]=type[v]^1;
dfs(id[i]);
continue;
}
ll j=-mn.get(a[v],b[v]);
if(a[v]>j){
type[id[j]]=type[v]^1;
dfs(id[j]);
continue;
}
break;
}
}
bool check(vll v){
for(auto i : v){
mn.upd(b[i],-a[i]);
mx.upd(a[i],b[i]);
}
for(auto i : v){
ll x=mx.get(a[i],b[i]);
if(x>b[i])return true;
x=-mn.get(a[i],b[i]);
if(a[i]>x)return true;
}
for(auto i : v){
mn.upd(b[i],-inf);
mx.upd(a[i],-inf);
}
return false;
}
void solve(){
ll i;
ll n;
cin>>n;
for(i=1;i<=n;i++){
cin>>a[i]>>b[i];
mx.upd(a[i],b[i]);
mn.upd(b[i],-a[i]);
id[a[i]]=i;
id[b[i]]=i;
}
ll ans=1;
for(i=1;i<=n;i++){
if(vis[i])continue;
vt[0].clear();
vt[1].clear();
dfs(i);
if(check(vt[1]) || check(vt[0])){
cout<<0<<endl;
return;
}
ans*=2;
ans%=mod;
}
cout<<ans<<endl;
}
signed main(){
//start();
ll t=1;
//cin>>t;
while(t--) solve();
return 0;
}
/*
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*/
