#include <bits/stdc++.h>
#define ff first
#define ss second
#define endl '\n'
using namespace std;
const long long INF = (long long) 1e18;
const int mod = (int) 1e9+7;
const int MAXN = (int) 2e6+5;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
ll n;
int t[4*MAXN][2];
int id[MAXN];
int yer[MAXN];
int sag[MAXN], sol[MAXN];
void build(int v, int tl, int tr){
if(tl == tr){
t[v][0] = t[v][1] = -1e9;
}else{
int tm = (tl + tr) / 2;
build(2*v, tl, tm);
build(2*v + 1, tm + 1, tr);
t[v][0] = t[v][1] = -1e9;
}
}
void upd(int v, int tl, int tr, int pos, int dis, int val){
if(tl == tr){
t[v][dis] = val;
}else{
int tm = (tl + tr) / 2;
if(pos <= tm)
upd(2*v, tl, tm, pos, dis, val);
else upd(2*v + 1 , tm + 1, tr, pos, dis, val);
t[v][dis] = max(t[2*v][dis], t[2*v + 1][dis]);
}
}
int get(int v, int tl, int tr, int l, int r, int dis){
if(l > r){
return -1e9;
}else if(tl == l && tr == r){
return t[v][dis];
}else{
int tm = (tl + tr) / 2;
ll ans1 = get(2*v, tl, tm, l, min(tm, r), dis);
ll ans2 = get(2*v + 1 ,tm + 1, tr, max(tm + 1 ,l), r, dis);
return max(ans1, ans2);
}
}
int cnt = 0;
void dfs(int ind, int angi){
//if(ind == 0) return;
//cout<<ind<<" "<<angi<<endl;
//if(cnt >= 100) return;
//cnt++;
yer[ind] = angi;
while(true){
int t = get(1, 1, 2*n, sol[ind] + 1, sag[ind] - 1, 0);
//cout<<t<<endl;
if(t < sag[ind]){
break;
}
upd(1, 1, 2*n, sol[id[t]], 0, -1e9);
upd(1, 1, 2*n, t, 1, -1e9);
//cout<<id[t]<<endl;
dfs(id[t], 3 - angi);
}
while(true){
int t = -get(1, 1, 2*n, sol[ind] + 1, sag[ind] - 1, 1);
//cout<<t<<endl;
//return;
if(t > sol[ind]){
break;
}
upd(1, 1, 2*n, t, 0, -1e9);
upd(1, 1, 2*n, sag[id[t]], 1, -1e9);
dfs(id[t], 3 - angi);
}
}
bool check(vector<pii> &ali){
stack<pii> st;
for(int i = 0; i < (int)ali.size(); i++){
while(!st.empty() && st.top().ss < ali[i].ff){
st.pop();
}
if(!st.empty() && ali[i].ff < st.top().ss && ali[i].ss > st.top().ss){
return 0;
}
st.push(ali[i]);
}
return 1;
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);cout.tie(nullptr);
#ifdef Local
freopen("../IO/int.txt","r",stdin);
freopen("../IO/out.txt","w",stdout);
#endif
cin>>n;
build(1, 1, 2*n);
for(int i = 1; i <= n; i++){
int l, r;
cin>>l>>r;
id[l] = i;
id[r] = i;
sag[i] = r;
sol[i] = l;
upd(1, 1, 2*n, l, 0, r);
upd(1, 1, 2*n, r, 1, -l);
}
ll ans = 1;
vector<pii> a1, a2;
for(int i = 1; i <= n; i++){
if(!yer[i]){
upd(1, 1, 2*n, sol[i], 0, -1e9);
upd(1, 1, 2*n, sag[i], 1, -1e9);
dfs(i, 1);
ans *= 2;
ans %= mod;
}
if(yer[i] == 1){
a1.push_back({sol[i], sag[i]});
}else{
a2.push_back({sol[i], sag[i]});
}
}
sort(a1.begin(), a1.end());
sort(a2.begin(), a2.end());
if(check(a1) && check(a2))
cout<<ans<<endl;
else cout<<0<<endl;
#ifdef Local
cout<<endl<<fixed<<setprecision(2)<<1000.0 * clock() / CLOCKS_PER_SEC<< " milliseconds ";
#endif
}
