#include <bits/stdc++.h>
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<ll, ll> pll;
typedef pair<ull, ull> pull;
typedef pair<int, int> pii;
typedef pair<ld, ld> pld;
const ll mod = 1e9+7;
ll pw(ll x, ll y){
ll ret = 1;
while(y){
if(y%2)
ret = x*ret%mod;
y /= 2;
x = x*x%mod;
}
return ret;
}
ll div2;
ll ans = 1;
vector<pair<int, pii>> ev;
pii a[1000009];
int st[1000009];
set<pii> s[3];
int n;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
//freopen("in.txt", "r", stdin);
//freopen("out.txt", "w", stdout);
cin >> n;
for(int i = 0; i < n; ++i){
cin >> a[i].ff >> a[i].ss;
ev.pb({a[i].ff, {i, 1}});
ev.pb({a[i].ss, {i, 0}});
}
ll div2 = pw(2, mod-2);
sort(ev.begin(), ev.end());
for(auto u : ev){
int id = u.ss.ff;
if(u.ss.ss == 0){
s[st[id]].erase({a[id].ss ,id});
continue;
}
auto it0 = s[0].lower_bound({a[id].ss, 0});
auto it1 = s[1].lower_bound({a[id].ss, 0});
auto it2 = s[2].lower_bound({a[id].ss, 0});
int curgroup;
if(it0 == s[0].begin() && it1 == s[1].begin())
curgroup = 2;
else if(it0 == s[0].begin())
curgroup = 0;
else if(it1 == s[1].begin())
curgroup = 1;
else{
cout << 0;
return 0;
}
if(it2 == s[2].begin()){
st[id] = curgroup;
s[curgroup].insert({a[id].ss, id});
if(curgroup == 2)
ans = ans*2%mod;
}
else{
if(curgroup == 2){
ans = ans*2%mod;
curgroup = 0;
}
st[id] = curgroup;
s[curgroup].insert({a[id].ss, id});
while(it2 != s[2].begin()){
--it2;
ans = ans*div2%mod;
st[it2->ss] = curgroup^1;
s[curgroup^1].insert(*it2);
it2 = s[2].erase(it2);
}
}
}
cout << ans << '\n';
}
