#include <bits/stdc++.h>
#include <assert.h>
#define FR(i, N) for (int i = 0; i < int(N); i++)
using namespace std;
using ll = long long;
const int MAXN = (int)(5e5) + 5;
int main() {
cin.tie(0);
cin.sync_with_stdio(0);
int N;
cin >> N;
vector<int> order;
order.resize(2*N);
FR(i, N) {
int a, b;
cin >> a >> b;
a--, b--;
order[a] = b;
order[b] = -a;
}
bool zero = false;
int cnt = 0;
vector<set<int>> intervals;
for (int i = 0; i < 2*N; i++) {
if (order[i] <= 0) {
intervals.back().erase(intervals.back().find(i));
if (intervals.back().size() == 0) {
intervals.pop_back();
cnt++;
}
}
else {
if (intervals.size() == 0) {
intervals.push_back({});
intervals.back().insert(order[i]);
}
else {
int j = intervals.size()-1;
intervals.push_back({});
intervals.back().insert(order[i]);
int track = 0;
while (j >= 0 && *intervals[j].begin() <= order[i]) {
for (int e : intervals[j]) {
if (e <= order[i]) {
track++;
}
}
intervals[j].insert(intervals[j+1].begin(), intervals[j+1].end());
intervals.pop_back();
j--;
}
// cout << track << '\n';
if (track >= 2) {
zero = true;
break;
}
}
}
}
ll tot = !zero;
ll MOD = (int)(1e9) + 7;
FR(i, cnt) {
tot += tot;
if (tot >= MOD) {
tot -= MOD;
}
}
assert (tot > 0);
cout << tot << '\n';
return 0;
}
