// I stand with PALESTINE
//#pragma GCC optimize("Ofast")
//#pragma GCC optimize ("unroll-loops")
//#pragma GCC target("avx,avx2")
#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
//using namespace __gnu_pbds;
// #define int long long
#define ff first
#define ss second
#define sz(a) (int) (a).size()
//template<class T, class C = null_type> using ordered_tree = tree<T, C, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long double ld;
namespace io {
template<typename F, typename S>
ostream &operator<<(ostream &os, const pair<F, S> &p) { return os << p.ff << " " << p.ss; }
template<typename F, typename S>
ostream &operator<<(ostream &os, const map<F, S> &mp) {
for (auto it: mp) { os << it << endl; }
return os;
}
template<typename F>
ostream &operator<<(ostream &os, const vector<F> &v) {
bool space = false;
for (F x: v) {
if (space) os << " ";
space = true;
os << x;
}
return os;
}
template<typename F>
ostream &operator<<(ostream &os, const deque<F> &d) {
bool space = false;
for (F x: d) {
if (space) os << " ";
space = true;
os << x;
}
return os;
}
template<typename F>
ostream &operator<<(ostream &os, const set<F> &st) {
bool space = false;
for (F x: st) {
if (space) os << " ";
space = true;
os << x;
}
return os;
}
template<typename F>
ostream &operator<<(ostream &os, const multiset<F> &st) {
bool space = false;
for (F x: st) {
if (space) os << " ";
space = true;
os << x << x;
}
return os;
}
template<typename F, typename S>
istream &operator>>(istream &is, pair<F, S> &p) { return is >> p.ff >> p.ss; }
template<typename F>
istream &operator>>(istream &is, vector<F> &v) {
for (F &x: v) { is >> x; }
return is;
}
long long fastread() {
char c;
long long d = 1, x = 0;
do c = getchar(); while (c == ' ' || c == '\n');
if (c == '-') c = getchar(), d = -1;
while (isdigit(c)) {
x = x * 10 + c - '0';
c = getchar();
}
return d * x;
}
static bool sep = false;
using std::to_string;
string to_string(bool x) {
return (x ? "true" : "false");
}
string to_string(const string &s) { return "\"" + s + "\""; }
string to_string(const char *s) { return "\"" + string(s) + "\""; }
string to_string(const char &c) {
string s;
s += c;
return "\'" + s + "\'";
}
template<typename Type>
string to_string(vector<Type>);
template<typename F, typename S>
string to_string(pair<F, S>);
template<typename Collection>
string to_string(Collection);
template<typename F, typename S>
string to_string(pair<F, S> p) { return "{" + to_string(p.ff) + ", " + to_string(p.ss) + "}"; }
template<typename Type>
string to_string(vector<Type> v) {
bool sep = false;
string s = "[";
for (Type x: v) {
if (sep) s += ", ";
sep = true;
s += to_string(x);
}
s += "]";
return s;
}
template<typename Collection>
string to_string(Collection collection) {
bool sep = false;
string s = "{";
for (auto x: collection) {
if (sep) s += ", ";
sep = true;
s += to_string(x);
}
s += "}";
return s;
}
void print() {
cout << endl;
sep = false;
}
template<typename F, typename... Other>
void print(F ff, Other... other) {
if (sep) cout << " | ";
sep = true;
cout << to_string(ff);
print(other...);
}
}
using namespace io;
namespace utils {
template<typename F, typename S>
inline void maxs(F &a, S b) { a = a > b ? a : b; }
template<typename F, typename S>
inline void mins(F &a, S b) { a = a < b ? a : b; }
template<typename F, typename S>
long long max(F a, S b) { return a > b ? a : b; }
template<typename F, typename S>
long long min(F a, S b) { return a < b ? a : b; }
constexpr long long operator "" _E(unsigned long long n) {
long long p = 1, a = 10;
for (int i = 0; i < n; i++) p *= a;
return p;
}
random_device rd;
mt19937 mt(rd());
template<typename T>
T rand(T l, T r) {
uniform_int_distribution<T> dist(l, r);
return dist(mt);
};
}
using namespace utils;
#ifdef sunnatov
#define print(...) cout << "[" << #__VA_ARGS__ << "]: "; io::print( __VA_ARGS__ );
#else
#define print( ... ) 42
#endif
const int mod = 9_E + 7;
const double EPS = 1e-7;
long long doxuya = 18_E + 10;
int INF = 9_E + 10;
const char nl = '\n';
int month[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
/*
*/
template<typename T> struct SegTree {
vector<T> tree;
int size;
T neutral_element = 0; // sum - 0, mx - (-INF), mn - INF
inline T merge(T a, T b) {
return a | b;
}
void init(int n) {
size = 1;
while (size <= n) size *= 2;
tree.assign(2 * size, neutral_element);
}
void build(vector<T> &a) {
size = 1;
while (size < a.size()) size *= 2;
tree.assign(2 * size, neutral_element);
for (int i = size; i < size + a.size(); i++) tree[i] = a[i - size];
for (int i = size - 1; i > 0; i--) tree[i] = merge(tree[i << 1], tree[i << 1 | 1]);
}
void upd(int p, T value) { // upd value at position p
p += size;
tree[p] = value;
for (; p > 1; p >>= 1) tree[p >> 1] = merge(tree[p], tree[p ^ 1]);
}
T get(int l, int r) { // sum on interval [l, r]
if (l > r) return neutral_element;
T res = neutral_element;
for (l += size, r += size + 1; l < r; l >>= 1, r >>= 1) {
if (l & 1) res = merge(res, tree[l++]);
if (r & 1) res = merge(res, tree[--r]);
}
return res;
}
};
int solve(int n, vector<pair<int, int>> a) {
sort(a.begin(), a.end());
vector<vector<int>> g(n + 1);
for (int i = 0; i < n; i++) {
for (int j = i + 1; j < n; j++) {
// print(i, j, a[i], a[j]);
if (a[j].ff < a[i].ss and a[i].ss < a[j].ss) {
g[i].emplace_back(j);
g[j].emplace_back(i);
}
}
}
vector vis(n, false);
vector<int> color(n + 1, -1);
auto dfs = [&](auto &dfs, int u) -> bool {
if (color[u] == -1) color[u] = 0;
vis[u] = true;
for (int v: g[u]) {
if (color[v] == -1) color[v] = 1 - color[u];
// print(u, v, color[u], color[v]);
if (color[v] == color[u]) return false;
if (!vis[v]) {
if (!dfs(dfs, v)) return false;
}
}
return true;
};
print(g);
int ans = 1;
for (int i = 0; i < n; i++) {
if (vis[i]) continue;
if (!dfs(dfs, i)) ans = 0;
else ans = ans * 2 % mod;
}
return ans;
}
void solution(istream &cin, ostream &cout, const int &test_case) {
int n;
cin >> n;
vector<pair<int, int>> a(n);
cin >> a;
sort(a.begin(), a.end());
SegTree<int> sg; sg.init(2 * n + 1);
vector<int> pos(2 * n + 1);
for (int i = 0; i < n; i++) pos[a[i].ff] = pos[a[i].ss] = i;
set<int> st;
vector<set<int>> vec(n);
vector<int> par(n), have(n), color(n);
for (int i = 0; i < n; i++) {
par[i] = i;
vec[i].insert(a[i].ss);
have[i] = a[i].ss;
}
auto merge = [&](int u, int v, int now) -> void {
int change = color[u] ^ color[v] ^ 1;
u = par[u]; v = par[v];
if (sz(vec[u]) > sz(vec[v])) swap(u, v);
st.erase(have[u]);
st.erase(have[v]);
for (int x: vec[u]) {
vec[v].insert(x);
par[pos[x]] = v;
color[pos[x]] ^= change;
}
vec[u].clear();
have[v] = *vec[v].lower_bound(now);
st.insert(have[v]);
};
for (int x = 1; x <= 2 * n; x++) {
int i = pos[x];
if (a[i].ff == x) {
st.insert(a[i].ss);
while (true) {
auto it = st.upper_bound(a[i].ff);
if (it == st.end() or *it > a[i].ss) break;
if (*it == have[par[i]]) it++;
if (it == st.end() or *it > a[i].ss) break;
print(i, pos[*it]);
merge(i, pos[*it], x);
}
} else {
if (have[par[i]] == x) {
st.erase(x);
auto it = vec[par[i]].upper_bound(x);
if (it != vec[par[i]].end()) {
st.insert(*it);
have[par[i]] = *it;
}
}
}
}
// for (int i = 0; i < n; i++) {
// if (vec[i].empty()) continue;
// for (int x: vec[i]) cout << pos[x] << ' ';
// cout << endl;
// }
for (int x = 1; x <= 2 * n; x++) {
int i = pos[x];
if (a[i].ff == x) {
color[i] = 1 << color[i];
if ((sg.get(a[i].ff, a[i].ss) & color[i]) == color[i]) {
cout << 0;
return;
}
sg.upd(a[i].ss, color[i]);
}
}
int ans = 1;
for (int i = 0; i < n; i++) if (par[i] == i) ans = ans * 2 % mod;
cout << ans;
}
int32_t main() {
clock_t startTime = clock();
cin.tie(0)->sync_with_stdio(false);
srand(time(0));
std::istream &in(std::cin);
std::ostream &out(std::cout);
int32_t queries = 1;
#ifdef test_cases
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
cin >> queries;
#else
// cin >> queries;
#endif
for (int32_t test_case = 1; test_case <= queries; test_case++) {
print(test_case);
solution(cin, cout, test_case);
cout << nl;
}
#ifdef sunnatov
cout << "Time: " << (int) ((double) (clock() - startTime) / CLOCKS_PER_SEC * 1000) << " ms" << endl;
#endif
return EXIT_SUCCESS;
}
