#include <bits/stdc++.h>
using namespace std;
#define int long long
const int mod = 1e9+7;
int p[4001], sz[4001], conn = 0, ans = 1;
set<int> disc;
int find(int u) {
return p[u] == u ? u : p[u] = find(p[u]);
}
void merge(int u, int v) {
u = find(u), v = find(v);
if (u == v) return;
if (sz[u] < sz[v]) swap(u, v);
p[v] = u, sz[u] += sz[v];
}
int32_t main() {
ios::sync_with_stdio(0); cin.tie(0);
int n;
cin >> n;
vector<int> a(n+1), b(n+1);
for (int i = 1; i <= n; i++) cin >> a[i] >> b[i];
for (int i = 1; i <= 2 * n; i++) p[i] = i, sz[i] = 1;
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= n; j++) {
if (i == j) continue;
if (a[i] < a[j] && a[j] < b[i] && b[i] < b[j]) {
merge(i, j + n);
merge(i + n, j);
}
}
}
for (int i = 1; i <= n; i++) if (find(i) == find(i + n)) {
cout << "0\n";
return 0;
}
for (int i = 1; i <= 2 * n; i++) {
int x = find(i);
if (x > n) x -= n;
disc.insert(x);
}
conn = disc.size();
for (int i = 1; i <= conn; i++) ans = ans * 2 % mod;
cout << ans << '\n';
}
