#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define ar array
#define vt vector
#define pq priority_queue
#define pu push
#define pub push_back
#define em emplace
#define emb emplace_back
#define mt make_tuple
#define all(x) x.begin(), x.end()
#define allr(x) x.rbegin(), x.rend()
#define allp(x, l, r) x.begin() + l, x.begin() + r
#define len(x) (int)x.size()
#define uniq(x) unique(all(x)), x.end()
using ll = long long;
using ld = long double;
using ull = unsigned long long;
template<class Fun> class y_combinator_result {
Fun fun_;
public:
template<class T> explicit y_combinator_result(T &&fun): fun_(std::forward<T>(fun)) {}
template<class ...Args> decltype(auto) operator()(Args &&...args) { return fun_(std::ref(*this), std::forward<Args>(args)...); }
};
template<class Fun> decltype(auto) y_combinator(Fun &&fun) { return y_combinator_result<std::decay_t<Fun>>(std::forward<Fun>(fun)); }
template <class T, size_t N>
void re(array <T, N>& x);
template <class T>
void re(vt <T>& x);
template <class T>
void re(T& x) {
cin >> x;
}
template <class T, class... M>
void re(T& x, M&... args) {
re(x), re(args...);
}
template <class T>
void re(vt <T>& x) {
for(auto& it : x) re(it);
}
template <class T, size_t N>
void re(array <T, N>& x) {
for(auto& it : x) re(it);
}
template <class T, size_t N>
void wr(const array <T, N>& x);
template <class T>
void wr(const vt <T>& x);
template <class T>
void wr(const T& x) {
cout << x;
}
template <class T, class ...M>
void wr(const T& x, const M&... args) {
wr(x), wr(args...);
}
template <class T>
void wr(const vt <T>& x) {
for(auto it : x) wr(it, ' ');
}
template <class T, size_t N>
void wr(const array <T, N>& x) {
for(auto it : x) wr(it, ' ');
}
template<class T, class... M>
auto mvt(size_t n, M&&... args) {
if constexpr(sizeof...(args) == 1)
return vector<T>(n, args...);
else
return vector(n, mvt<T>(args...));
}
void set_fixed(int p = 0) {
cout << fixed << setprecision(p);
}
void set_scientific() {
cout << scientific;
}
void Open(const string& name) {
#ifndef ONLINE_JUDGE
(void)!freopen((name + ".in").c_str(), "r", stdin);
(void)!freopen((name + ".out").c_str(), "w", stdout);
#endif
}
const int N = 1e6 + 5;
vt <int> adj[N];
int cnt;
int col[N];
int nxt[N], par[N], le[N], id[N << 1], a[N];
inline int find(int u) {
return par[u] == u? u : par[u] = find(par[u]);
}
inline void add_edge(int u, int v) {
adj[u].emb(v);
adj[v].emb(u);
}
bool dfs(int u, int c) {
col[u] = c;
for (auto& v : adj[u]) {
if (!col[v]) {
if (!dfs(v, 3 - c))
return false;
}
if (col[v] == col[u]) {
return false;
}
}
return true;
}
void solve() {
int n; re(n);
for (int i = 1; i <= n; ++i) {
int l, r; re(l, r);
id[l] = id[r] = i;
}
for (int i = 1; i <= n; ++i)
nxt[i] = par[i] = i;
par[n + 1] = n + 1;
for (int i = 1; i <= 2 * n; ++i) {
int p = id[i];
if (!le[p]) a[++cnt] = p, le[p] = cnt;
else {
int u = le[p];
par[u] = find(u + 1);
for (int j = par[u], k; j <= cnt; j = k) {
add_edge(a[j], p);
k = find(nxt[j] + 1);
nxt[j] = cnt;
}
}
}
int cc = 0;
for (int i = 1; i <= n; ++i)
if (!col[i]) {
if (dfs(i, 1)) ++cc;
else return wr("0\n");
}
const int mod = 1e9 + 7;
ll res = 1;
for (int i = 0; i < cc; ++i)
res = (res * 2) % mod;
wr(res);
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
//Open("");
int t = 1;
for(;t;t--) {
solve();
}
return 0;
}
