#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define fbo find_by_order
#define ook order_of_key
#define f first
#define s second
#define pb push_back
#define reset(a,b) memset(a,b,sizeof a);
#define MOD 1000000007
#define MID (l+r)/2
#define ALL(x) x.begin(),x.end()
#define debug(x) cout<<#x<<" = "<<(x)<<endl
#define mx 2000003
#define pc(x) putchar_unlocked(x);
typedef tree<long long, null_type, less<long long>, rb_tree_tag, tree_order_statistics_node_update> pbds;
vector<int>ve[mx*4];
pair<int,int>a[mx];
int n,par[mx];
int find(int x){
// debug(x);
if(x==par[x])return x;
return par[x]=find(par[x]);
}
void gabung(int idx,int l,int r,int fl,int fr,int val){
if(fl>r || fr<l)return;
if(ve[idx].size()==0)return;
if(fl<=l && r<=fr){
// debug(val);
for(int i:ve[idx]){
int j=i;
if(j<=n)j+=n;
else j-=n;
i=find(i);
// debug(i);
j=find(j);
par[i]=find(val+n);
par[j]=find(val);
}
ve[idx].clear();
ve[idx].pb(find(val+n));
return;
}
if(!(fl>MID || fr<l))gabung(idx*2,l,MID,fl,fr,val);
if(!(fl>r || fr<MID+1))gabung(idx*2+1,MID+1,r,fl,fr,val);
}
void upd(int idx,int l,int r,int in,int val){
ve[idx].pb(find(val));
if(l==r)return;
if(in<=MID)upd(2*idx,l,MID,in,val);
else upd(2*idx+1,MID+1,r,in,val);
}
int main(){
scanf("%d",&n);
for(int i=1;i<=n;i++)scanf("%d%d",&a[i].f,&a[i].s);
sort(a+1,a+n+1);
for(int i=1;i<=n*2;i++){
par[i]=i;
}
for(int i=1;i<=n;i++){
gabung(1,1,n*2,a[i].f,a[i].s,i);
upd(1,1,n*2,a[i].s,i);
}
for(int i=1;i<=n;i++){
// debug(i);
int x=find(i);
int y=find(i+n);
if(x==y){
// debug(i);
cout<<0<<endl;
return 0;
}
}
set<int>isi;
for(int i=1;i<=n*2;i++){
isi.insert(find(i));
}
int tot=isi.size();
assert(tot%2==0);
tot/=2;
long long jaw=1;
for(int i=1;i<=tot;i++){
jaw=jaw*2%MOD;
}
cout<<jaw<<endl;
}
