#include <iostream>
#include <iomanip>
#include <vector>
#include <cmath>
#include <algorithm>
#include <set>
#include <queue>
#include <map>
#include <unordered_map>
#include <stack>
#include <bit>
#include <bitset>
#include <string>
#include <cstring>
#include <iterator>
#include <random>
#define ll long long
#define ld long double
#define inf (ll)(2*1e18)
#define sort(a) sort(a.begin(), a.end())
#define reverse(a) reverse(a.begin(), a.end())
#define pb push_back
#define endl "\n"
using namespace std;
ll mod=1e9+7;
ll binPow(ll a, ll n){
    ll res = 1, b=a;
    while(n){
        if(n&1){
            res *= b;
            res %= mod;
            --n;
        }
        b *= b;
        b %= mod;
        n /= 2;
    }
    return res;
}
void solve(){
    ll n, i, l, r, cnt=0, id, x;
    cin>>n;
    vector<pair<ll, ll>> add(2*n);
    vector<ll> a(n);
    vector<ll> b(n);
    set<ll> s;
    for(i=0;i<n;++i){
        cin>>l>>r;
        --l;
        --r;
        add[l] = {r, i};
        add[r] = {l, i};
    }
    for(i=0;i<2*n;++i){
        x = add[i].first;
        id = add[i].second;
        if(i < x){
            s.insert(x);
            auto it = s.find(x);
            if(it == s.begin()){
                ++cnt;
                a[id] = -inf;
            }else{
                --it;
                a[id] = *it;
            }
        }else{
            s.erase(i);
        }
    }
    for(i=2*n-1;i>=0;--i){
        x = add[i].first;
        id = add[i].second;
        if(i > x){
            s.insert(x);
            auto it = s.find(x);
            ++it;
            if(it == s.end()){
                b[id] = inf;
            }else{
                b[id] = *it;
            }
        }else{
            s.erase(i);
        }
    }
    for(i=0;i<n;++i){
        if(a[i] > b[i]){
            cout<<0<<endl;
            return;
        }
    }
    cout<<binPow(2, cnt)<<endl;
}
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    srand(time(nullptr));
    ll t=1;
//    cin>>t;
    for(;t>0;--t){
        solve();
    }
    return 0;
}
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