#include <iostream>
#include <vector>
#include <set>
#include <algorithm>
using namespace std;
const int N = (1<<21) + 1;
int pr[N<<1], cnt[N<<1], Seen[N], Par[N];
int root(int v){
return (Par[v] == 0 or Par[v] == v ? v : Par[v] = root(Par[v]));
}
void change(int id, int vl){
if (cnt[id] == 0)
pr[id] = 0;
if (pr[id])
Par[root(pr[id])] = vl;
pr[id] = vl;
}
void push(int cur, int lc, int rc){
change(lc, pr[cur]);
change(rc, pr[cur]);
pr[cur] = 0;
}
void insert(int l, int r, int cur = 1, int st = 1, int en = N){
// cout<<cur<<" "<<st<<" "<<en<<endl;
if (l >= en or r <= st)
return;
if (l <= st and r >= en){
change(cur, r);
return;
}
int lc = cur + cur, rc = lc + 1, mid = (st + en) / 2;
if (pr[cur])
push(cur, lc, rc);
insert(l, r, lc, st, mid);
insert(l, r, rc, mid, en);
}
void Add(int i, int cur = 1, int st = 1, int en = N){
if (i >= en or i < st)
return;
cnt[cur]++;
if (en - st == 1){
pr[cur] = i;
return;
}
int lc = cur + cur, rc = lc + 1, mid = (st + en) / 2;
if (pr[cur])
push(cur, lc, rc);
Add(i, lc, st, mid);
Add(i, rc, mid, en);
}
void process(int cur = 1, int st = 1, int en = N){
if (en - st == 1){
return;
}
int lc = cur + cur, rc = lc + 1, mid = (st + en) / 2;
if (pr[cur])
push(cur, lc, rc);
process(lc, st, mid);
process(rc, mid, en);
}
int main(){
int n, Ans = 1, mod = 1e9 + 7;
cin>>n;
vector<pair<int, int>> vec;
for (int i=1, a, b;i<=n;i++){
cin>>a>>b;
vec.push_back({a, b});
}
sort(begin(vec), end(vec));
for (auto [l, r] : vec){
insert(l, r);
Add(r);
}
process();
set<int> A = {0}, B = {0};
for (auto [l, r] : vec){
if (*prev(A.upper_bound(r)) <= l)
A.insert(r);
else if (*prev(B.upper_bound(r)) <= l)
B.insert(r);
else
Ans = 0;
Seen[root(r)] = 1;
}
for (int i=1;i<N;i++){
Ans = Ans + Ans * Seen[i];
if (Ans >= mod)
Ans -= mod;
}
cout<<Ans<<'\n';
}
