#include <bits/stdc++.h>
using namespace std;
using pii = pair<int, int>;
#define ff first
#define ss second
const int mod = 1e9 + 7;
int mp(int x, int a) {
if (a == 0) return 1;
int ret = mp(x, a >> 1);
if (a & 1) return 1ll * ret * ret % mod * x % mod;
return 1ll * ret * ret % mod;
}
int N;
pii P[1000005];
const int SIZE = 1 << 20;
struct ST {
set<int> A[2 * SIZE];
void insert(int x, int v) {
for (x += SIZE; x; x >>= 1) A[x].insert(v);
}
void erase(int x, int v) {
for (x += SIZE; x; x >>= 1) A[x].erase(v);
}
vector<int> query(int s, int e, int a, int b) {
vector<int> ret;
for (s += SIZE, e += SIZE; s <= e; s >>= 1, e >>= 1) {
if ( s & 1) {
auto i = A[s].lower_bound(a);
auto j = A[s].lower_bound(b);
for (; i != j; ++i) ret.push_back(*i);
s++;
}
if (~e & 1) {
auto i = A[e].lower_bound(a);
auto j = A[e].lower_bound(b);
for (; i != j; ++i) ret.push_back(*i);
e--;
}
}
return ret;
}
} seg;
bool vis[1000005], C[1000005];
vector<int> A, B;
void dfs(int x) {
if (C[x]) A.push_back(x);
else B.push_back(x);
vis[x] = 1;
auto v = seg.query(P[x].ff, P[x].ss, 0, x);
auto u = seg.query(P[x].ss, 2 * N, x, N);
for (auto i : v) seg.erase(P[i].ss, i);
for (auto i : u) seg.erase(P[i].ss, i);
for (auto i : v) C[i] = C[x] ^ 1, dfs(i);
for (auto i : u) C[i] = C[x] ^ 1, dfs(i);
}
int main() {
cin >> N;
for (int i = 0; i < N; ++i) {
int a, b; cin >> a >> b;
P[i] = {a, b};
}
sort(P, P + N);
for (int i = 0; i < N; ++i) seg.insert(P[i].ss, i);
int cnt = 0;
for (int i = N - 1; i >= 0; --i) {
if (vis[i]) continue;
cnt++;
seg.erase(P[i].ss, i);
dfs(i);
}
priority_queue<int, vector<int>, greater<int> > pq;
sort(A.begin(), A.end());
sort(B.begin(), B.end());
for (auto i : A) {
while (pq.size() && pq.top() < P[i].ff) pq.pop();
if (pq.size() && pq.top() < P[i].ss) return !printf("0");
pq.push(P[i].ss);
}
while (pq.size()) pq.pop();
for (auto i : B) {
while (pq.size() && pq.top() < P[i].ff) pq.pop();
if (pq.size() && pq.top() < P[i].ss) return !printf("0");
pq.push(P[i].ss);
}
cout << mp(2, cnt);
return 0;
}
