#include <bits/stdc++.h>
using namespace std;
typedef pair<int, int> ii;
typedef pair<int, bool> p;
const int N = 1000005;
const int MOD = 1e9 + 7;
int n, cnt, c[N];
int it[8 * N];
int prv[25 * N];
p val[25 * N];
vector<ii> a;
vector<p> G[N];
void NO() {
cout << 0 << '\n'; exit(0);
}
void addEdge(int u, int v, bool w) {
G[u].push_back(p(v, w)), G[v].push_back(p(u, w));
}
void upd(int i, int l, int r, int x, int id) {
++cnt, prv[cnt] = it[i], val[cnt] = p(id, 0), it[i] = cnt;
if (l == r) return;
int mid = (l + r) >> 1;
if (mid >= x) upd(i << 1, l, mid, x, id);
else upd(i << 1 | 1, mid + 1, r, x, id);
}
void get(int i, int l, int r, int u, int v, int id) {
if (l > v || u > r) return;
if (u <= l && r <= v) {
if (!it[i]) return;
int cur = it[i];
while (cur) {
addEdge(id, val[cur].first, val[cur].second ^ 1), cur = prv[cur];
}
val[it[i]] = ii(id, 1), prv[it[i]] = 0;
return;
}
int mid = (l + r) >> 1;
get(i << 1, l, mid, u, v, id);
get(i << 1 | 1, mid + 1, r, u, v, id);
}
void dfs(int u) {
for (auto v : G[u]) {
if (c[v.first] != -1 && (c[u] ^ v.second) != c[v.first]) NO();
if (c[v.first] != -1) continue;
c[v.first] = c[u] ^ v.second, dfs(v.first);
}
}
int main() {
scanf("%d", &n);
for (int i = 0; i < n; ++i) {
int x, y;
scanf("%d %d", &x, &y);
a.push_back(ii(x, y));
}
sort(a.begin(), a.end());
for (int i = 0; i < n; ++i) {
get(1, 1, 2 * n, a[i].first, a[i].second, i);
upd(1, 1, 2 * n, a[i].second, i);
}
memset(c, -1, sizeof(c));
int num = 0;
for (int i = 0; i < n; ++i) {
if (c[i] != -1) continue;
c[i] = 1, dfs(i), num++;
}
int res = 1;
for (int i = 0; i < num; ++i) res = 1LL * res * 2 % MOD;
cout << res << '\n';
}
