#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "deb.h"
#else
#define debug(...)
#endif
const int M = 1e9 + 7;
void solve() {
int n;
cin >> n;
vector<int> a(n), b(n), d(2 * n);
for (int i = 0; i < n; i++) {
cin >> a[i] >> b[i];
--a[i]; --b[i];
d[a[i]] = i + 1;
d[b[i]] = -i - 1;
}
vector<vector<int>> g(n);
auto Add = [&](int u, int v) -> void {
--u; --v;
g[u].push_back(v);
g[v].push_back(u);
};
set<int> active;
for (int i = 0; i < 2 * n; i++) {
if (d[i] > 0) {
active.insert(d[i]);
} else {
active.erase(-d[i]);
for (int obstacle : active) {
if (a[obstacle - 1] > a[-d[i] - 1]) {
Add(obstacle, -d[i]);
}
}
}
}
vector<int> c(n, -1);
bool bipartite = true;
int comps = 0;
auto Dfs = [&](auto&& self, int v) -> void {
for (int u : g[v]) {
if (c[u] == c[v]) {
bipartite = false;
return;
} else {
if (c[u] == -1) {
c[u] = c[v] ^ 1;
self(self, u);
}
}
}
};
for (int i = 0; i < n; i++) {
if (c[i] == -1) {
comps += 1;
c[i] = 0;
Dfs(Dfs, i);
}
}
if (!bipartite) {
cout << 0 << '\n';
return;
}
int ans = 1;
for (int i = 0; i < comps; i++) {
ans *= 2;
ans %= M;
}
cout << ans << '\n';
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
int t = 1;
// cin >> t;
while (t--) {
solve();
}
return 0;
}
