#include<bits/stdc++.h>
using namespace std;
typedef long double ld;
typedef long long ll;
#define rep(a, b) for(int a = 0; a < (b); ++a)
#define st first
#define nd second
#define pb push_back
#define all(a) a.begin(), a.end()
const ll MOD=1e9+7;
const int LIM=1e6+7;
pair<int,int>T[LIM];
int F[LIM], S[2*LIM], odw[LIM], sum[LIM];
int fnd(int x) {
if(F[x]==x) return x;
return F[x]=fnd(F[x]);
}
void uni(int a, int b) {
if(fnd(a)==fnd(b)) return;
F[fnd(b)]=fnd(a);
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
int n;
cin >> n;
rep(i, n) {
cin >> T[i].st >> T[i].nd;
--T[i].st; --T[i].nd;
}
sort(T, T+n);
vector<int>A, B;
A.pb(MOD);
B.pb(MOD);
rep(i, n) {
while(A.back()<T[i].st) A.pop_back();
while(B.back()<T[i].st) B.pop_back();
if(T[i].nd>max(A.back(), B.back())) {
cout << 0 << '\n';
return 0;
}
if(A.back()<=B.back()) {
if(T[i].nd<A.back()) A.pb(T[i].nd);
else B.pb(T[i].nd);
} else {
if(T[i].nd<B.back()) B.pb(T[i].nd);
else A.pb(T[i].nd);
}
}
rep(i, n) F[i]=i;
rep(i, n) {
S[T[i].st]=i+1;
S[T[i].nd]=-i-1;
}
vector<int>P;
rep(i, 2*n) {
int p=abs(S[i])-1;
if(S[i]>0) {
P.pb(p);
continue;
}
vector<int>C;
while(P.back()!=p) {
C.pb(P.back());
P.pop_back();
}
P.pop_back();
while(C.size()>0) {
P.pb(C.back());
uni(p, C.back());
C.pop_back();
}
}
ll ans=1;
rep(i, n) if(fnd(i)==i) ans=(ans*2)%MOD;
cout << ans << '\n';
}
