#include <iostream>
#include <vector>
#include <algorithm>
#include <cassert>
// acm doar trb sa dau lock in si sa bag jmenu lui voicu
// daca e raspunsu 0 e jover :sob: :pray:
using ll = long long;
#define debug(x) #x << " = " << x << '\n'
const int NMAX = 1e6;
const int mod = 1e9 + 7;
std::vector<int> sweep[2 * NMAX + 1];
struct Container {
int x, y;
bool operator < (const Container &other) const {
return x != other.x? x < other.x : y < other.y;
};
};
Container a[NMAX + 1];
namespace DSU {
std::vector<int> p;
std::vector<int> color;
void init(int n) {
p.resize(n + 1);
color.resize(n + 1, 0);
for (int i = 1; i <= n; i++) {
p[i] = i;
color[i] = 0;
}
}
int root(int u) {
return p[u] == u? u : p[u] = root(p[u]);
}
bool join(int u, int v) {
u = root(u);
v = root(v);
if (u != v) {
p[u] = v;
} else {
if (color[u] == color[v]) {
return false;
}
}
return true;
}
};
int main() {
#ifdef LOCAL
freopen("input.txt", "r", stdin);
#endif
std::ios_base::sync_with_stdio(false);
std::cin.tie(0);
int n;
std::cin >> n;
for (int i = 1; i <= n; i++) {
std::cin >> a[i].x >> a[i].y;
}
std::sort(a + 1, a + n + 1);
for (int i = 1; i <= n; i++) {
sweep[a[i].x].push_back(i);
}
if (n <= 2000) {
DSU::init(n);
for (int i = 1; i < n; i++) {
for (int j = i + 1; j <= n; j++) {
if (a[i].y > a[j].x && a[i].y < a[j].y) {
if (!(DSU::join(i, j))) {
std::cout << 0;
return 0;
}
}
}
}
}
DSU::init(n);
std::vector<int> maxR(2 * n + 1, -1);
std::vector<int> who(2 * n + 1, -1);
auto activate = [&](int index) {
maxR[a[index].x] = a[index].y;
who[a[index].x] = index;
};
auto deactivate = [&](int index) {
maxR[a[index].x] = -1;
who[a[index].x] = -1;
};
auto query = [&](int l, int r) {
int maxi = -1, index = -1;
for (int i = l; i <= r; i++) {
if (maxR[i] > maxi) {
maxi = maxR[i];
index = who[i];
}
}
return index;
};
DSU::init(n);
int answer = 1;
for (int L = 2 * n; L > 0; L--) {
for (const auto &index : sweep[L]) {
auto [x, y] = a[index];
int other = query(x, y);
while (other != -1 && y < a[other].y) {
// std::cout << "JOIN: " << index << ' ' << other << '\n';
if (!DSU::join(index, other)) {
answer = 0;
break;
}
deactivate(other);
other = query(x, y);
}
activate(index);
}
}
if (answer != 0) {
for (int i = 1; i <= n; i++) {
if (DSU::root(i) == i) {
answer = 2 * answer % mod;
}
}
}
std::cout << answer;
return 0;
}
