#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 1e6 + 7;
const int M = 1e9 + 7;
const int INF = 2e9;
int add(int a, int b) {
return a + b >= M ? a + b - M : a + b;
}
int mul(int a, int b) {
return a * 1ll * b % M;
}
int n;
pair<int, int> a[N];
int ind[N];
int color[N];
struct segtree {
vector<int> tree;
segtree() {}
void init(int n) {
tree.resize(4 * n + 1);
build(1, 1, n);
}
void build(int v, int tl, int tr) {
tree[v] = -INF;
if (tl < tr) {
int tm = (tl + tr) / 2;
build(2 * v, tl, tm);
build(2 * v + 1, tm + 1, tr);
}
}
void update(int v, int tl, int tr, int pos, int val) {
if (tl == tr) {
tree[v] = val;
return;
}
int tm = (tl + tr) / 2;
if (pos <= tm) {
update(2 * v, tl, tm, pos, val);
} else {
update(2 * v + 1, tm + 1, tr, pos, val);
}
tree[v] = max(tree[2 * v], tree[2 * v + 1]);
}
int query(int v, int tl, int tr, int l, int r, int val) {
if (tr < l || tl > r) return -1;
if (l <= tl && tr <= r) {
if (tree[v] > val) {
if (tree[v] > 0) {
return ind[tree[v]];
} else {
return ind[tree[v] * -1];
}
}
return -1;
}
int tm = (tl + tr) / 2;
int ret = -1;
ret = query(2 * v, tl, tm, l, r, val);
if (ret != -1) {
return ret;
}
ret = query(2 * v + 1, tm + 1, tr, l, r, val);
return ret;
}
void delete_kek(int v, int tl, int tr, int pos) {
if (tl == tr) {
tree[v] = -INF;
return;
}
int tm = (tl + tr) / 2;
if (pos <= tm) {
delete_kek(2 * v, tl, tm, pos);
} else {
delete_kek(2 * v + 1, tm + 1, tr, pos);
}
tree[v] = max(tree[2 * v], tree[2 * v + 1]);
}
};
segtree kek1, kek2;
void dfs(int v, int c = 0) {
kek1.delete_kek(1, 1, 2 * n, a[v].first);
kek2.delete_kek(1, 1, 2 * n, a[v].second);
color[v] = c;
while (true) {
int i = kek1.query(1, 1, 2 * n, a[v].first, a[v].second, a[v].second);
if (i == -1) {
break;
}
dfs(i, 1 - c);
}
while (true) {
int i = kek2.query(1, 1, 2 * n, a[v].first, a[v].second, -a[v].first);
if (i == -1) {
break;
}
dfs(i, 1 - c);
}
}
bool check(vector<pair<int, int>> a) {
sort(a.begin(), a.end());
priority_queue<int, vector<int>, greater<int>> q;
for (int i = 0; i < a.size(); ++i) {
while (!q.empty() && q.top() < a[i].first) {
q.pop();
}
if (!q.empty() && q.top() < a[i].second) {
return 0;
}
q.push(a[i].second);
}
return 1;
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
cin >> n;
for (int i = 1; i <= n; ++i) {
cin >> a[i].first >> a[i].second;
}
kek1.init(2 * n);
kek2.init(2 * n);
for (int i = 1; i <= n; ++i) {
kek1.update(1, 1, 2 * n, a[i].first, a[i].second);
kek2.update(1, 1, 2 * n, a[i].second, -a[i].first);
ind[a[i].first] = ind[a[i].second] = i;
}
for (int i = 1; i <= n; ++i) {
color[i] = -1;
}
int ans = 1;
for (int i = 1; i <= n; ++i) {
if (color[i] == -1) {
ans = mul(ans, 2);
dfs(i);
}
}
vector<vector<pair<int, int>>> v(2);
for (int i = 1; i <= n; ++i) {
v[color[i]].push_back(a[i]);
}
if (check(v[0]) && check(v[1])) {
cout << ans << "\n";
} else {
cout << "0\n";
}
return 0;
}
