#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ull unsigned ll
#define ld long double
#define ff first
#define ss second
#define ln "\n"
const ll MOD = 1e9+7;
struct DSU{
vector<ll> p; vector<map<ll, ll>> nodes;
ll n, cnt;
DSU(ll N){
n=N; cnt=N; p.resize(n, -1);
nodes.resize(n);
for (ll i=0; i<n; i++) nodes[i][i]=0;
}
ll get(ll x){
return p[x]==-1?x:p[x]=get(p[x]);
}
bool unite(ll u, ll v){
ll iu=u, iv=v;
u=get(u); v=get(v);
if (u==v){
return nodes[u][iu]!=nodes[u][iv];
}
if (nodes[u].size()<nodes[v].size()) swap(u, v);
p[v]=u;
if (nodes[u][iu]==nodes[v][iv]){
for (auto &[x, val]:nodes[v]){
val^=1;
}
}
for (auto [x, val]:nodes[v]) nodes[u][x]=val;
cnt--; return 1;
}
};
void solve(){
ll n; cin >> n;
vector<ll> a(2*n+1);
vector<array<ll, 2>> rng(n);
for (ll i=0; i<n; i++){
ll l, r; cin >> l >> r;
a[l]=i; a[r]=i; rng[i] = {l, r};
}
set<array<ll, 2>> present;
DSU tr(n);
for (ll i=1; i<=2*n; i++){
if (!present.count({rng[a[i]][1], a[i]})){
for (auto [r, ind]:present){
if (r>rng[a[i]][1]) break;
if (!tr.unite(ind, a[i])){
cout << 0 << ln; return;
}
}
present.insert({rng[a[i]][1], a[i]});
}else{
present.erase({rng[a[i]][1], a[i]});
}
}
ll res=1;
for (ll i=0; i<tr.cnt; i++){
res=(res*2)%MOD;
}
cout << res << ln;
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(nullptr);
ll t=1;
// cin >> t;
while (t--) solve();
}
