/*
*/
#include <bits/stdc++.h>
using namespace std;
#define ff first
#define ss second
#define pb push_back
///#define ll long long
typedef pair<int,int> pii;
const int maxn=1e6+10;
int mod=1e9+7,e;
int levi[maxn],color[maxn],n,kolko,rez,grane;
pii niz[2*maxn];
vector<int>vect[maxn];
unordered_set<int>tree[(1<<22)+10];
void update(int x,int l,int r,int id,int val,int tip){
if(tip)tree[x].insert(val);
else tree[x].erase(val);
if(l==r)return;
int mid=(l+r)/2;
if(id<=mid)update(x*2,l,mid,id,val,tip);
else update(x*2+1,mid+1,r,id,val,tip);
}
void go(int x,int l,int r,int ll,int rr,int nd){
if(l>=ll && r<=rr){
for(unordered_set<int>::iterator it=tree[x].begin();it!=tree[x].end();it++){
int id=(*it);
vect[nd].pb(id);
vect[id].pb(nd);
grane++;
/// printf("%d IDID\n",id);
}
return;
}
int mid=(l+r)/2;
if(ll>mid)go(x*2+1,mid+1,r,ll,rr,nd);
else if(rr<=mid)go(x*2,l,mid,ll,rr,nd);
else{
go(x*2,l,mid,ll,rr,nd);
go(x*2+1,mid+1,r,ll,rr,nd);
}
}
void dfs(int x,int col){
color[x]=col;
for(int i=0;i<vect[x].size();i++){
int id=vect[x][i];
if(color[id]==col)rez=0;
else if(color[id]==-1)dfs(id,col^1);
}
}
int main(){
///freopen("test.txt","r",stdin);
clock_t start=clock();
scanf("%d",&n);
///int limit=30000000;
///if(n<=2000)limit=1e9;
memset(color,-1,sizeof(color));
for(int i=1;i<=n;i++){
int a,b;
scanf("%d %d",&a,&b);
niz[a]={i,1};
niz[b]={i,-1};
levi[i]=a;
}
for(int i=1;i<=2*n;i++){
if(niz[i].ss>0)update(1,1,2*n,i,niz[i].ff,1);
else{
int id=niz[i].ff;
int lb=levi[id];
update(1,1,2*n,lb,id,0);
///printf("%d AAAAA\n",id);
go(1,1,2*n,lb,i,id);
/*if(grane>limit){
printf("0\n");
return 0;
}*/
clock_t sad=clock();
if((double)(sad-start)/CLOCKS_PER_SEC>5){
printf("0\n");
return 0;
}
}
}
rez=1;
for(int i=1;i<=n;i++){
if(color[i]==-1){
dfs(i,0);
rez+=rez;
if(rez>=mod)rez-=mod;
}
}
printf("%d\n",rez);
return 0;
}
