#include <bits/stdc++.h>
using namespace std;
#define pii pair<int,int>
#define fs first
#define sc second
#define ll long long
const ll mod = 1e9+7;
const int mxn = 2e6+10;
ll pw(ll a,ll b){
ll re = 1;
while(b){
if(b&1)re = re*a%mod;
b>>=1;
a = a*a%mod;
}
return re;
}
ll mad(ll a,ll b){
a += b;
return a>=mod?a-mod:a;
}
void print(priority_queue<pii,vector<pii>,less<pii>> pq){
vector<pii> tmp;
while(!pq.empty()){
cerr<<pq.top().fs<<','<<pq.top().sc<<' ';
tmp.push_back(pq.top());
pq.pop();
}
cerr<<endl;
return;
}
struct DSU{
int dsu[mxn],sz[mxn];
priority_queue<pii,vector<pii>,less<pii>> pq[mxn];
DSU(){}
void init(int n){
for(int i = 0;i<=n;i++)dsu[i] = i,sz[i] = 1;
return;
}
int root(int k){
return k == dsu[k]?k:dsu[k] = root(dsu[k]);
}
void onion(int a,int b){
a = root(a),b = root(b);
if(a == b)return;
if(sz[a]<sz[b])swap(a,b);
dsu[b] = a;
sz[a] += sz[b];
if(pq[a].size()<pq[b].size())pq[a].swap(pq[b]);
while(!pq[b].empty()){
pq[a].push(pq[b].top());
pq[b].pop();
}
return;
}
};
pii arr[mxn];
int N;
int C = 0;
int col[mxn];
DSU dsu;
int op[mxn];
set<pii> st;
bitset<mxn> active;
void update(int r){
r = dsu.root(r);
if(!dsu.pq[r].empty()&&st.find(dsu.pq[r].top()) != st.end())st.erase(dsu.pq[r].top());
while(!dsu.pq[r].empty()&&!active[dsu.pq[r].top().sc])dsu.pq[r].pop();
if(!dsu.pq[r].empty())st.insert(dsu.pq[r].top());
return;
}
int main(){
ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
cin>>N;
dsu.init(N*2);
for(int i = 1;i<=N;i++){
cin>>arr[i].fs>>arr[i].sc;
op[arr[i].fs] = i;
op[arr[i].sc] = -i;
dsu.pq[i*2].push(pii(arr[i].fs,i));
}
for(int i = 1;i<=N*2;i++){
if(op[i]>0){
active[op[i]] = true;
update(op[i]*2);
continue;
}
int pos = -op[i];
active[pos] = false;
update(dsu.root(pos*2));
while(!st.empty()&&st.rbegin()->fs>arr[pos].fs){
if(active[st.rbegin()->sc]){
dsu.onion(pos*2-1,st.rbegin()->sc*2);
dsu.onion(pos*2,st.rbegin()->sc*2-1);
}
st.erase(*st.rbegin());
}
update(dsu.root(pos*2-1));
//cerr<<i<<":";for(auto &j:st)cerr<<j.fs<<','<<j.sc<<' ';cerr<<endl;
}
int ans = 0;
for(int i = 1;i<=N;i++){
if(dsu.root(i*2) == dsu.root(i*2-1)){
cout<<0;
return 0;
}
if(dsu.root(i*2) == i*2)ans++;
if(dsu.root(i*2-1) == i*2-1)ans++;
}
cout<<pw(2,ans>>1);
}
