#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];
int idx[2000005];
const int SIZE = 1 << 21;
struct ST {
vector<pii> A;
ST() { A.resize(2 * SIZE); }
void update(int x, int v) {
x += SIZE;
A[x] = {v, x - SIZE};
for (x >>= 1; x; x >>= 1) A[x] = max(A[x << 1], A[x << 1 | 1]);
}
pii query(int s, int e) {
pii ret = {0, 0};
for (s += SIZE, e += SIZE; s <= e; s >>= 1, e >>= 1) {
if ( s & 1) ret = max(ret, A[s++]);
if (~e & 1) ret = max(ret, A[e--]);
}
return ret;
}
} seg1, seg2;
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;
vector<int> v;
while (1) {
auto t = seg1.query(P[x].ff, P[x].ss);
if (2 * N + 1 - t.ff > P[x].ff) break;
seg1.update(t.ss, 0);
seg2.update(2 * N + 1 - t.ff, 0);
v.push_back(idx[2 * N + 1 - t.ff]);
}
while (1) {
auto t = seg2.query(P[x].ff, P[x].ss);
if (t.ff < P[x].ss) break;
seg1.update(t.ff, 0);
seg2.update(t.ss, 0);
v.push_back(idx[t.ss]);
}
for (auto i : v) 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) seg1.update(P[i].ss, 2 * N + 1 - P[i].ff), seg2.update(P[i].ff, P[i].ss), idx[P[i].ff] = i;
int cnt = 0;
for (int i = N - 1; i >= 0; --i) {
if (vis[i]) continue;
cnt++;
seg1.update(P[i].ss, 0);
seg2.update(P[i].ff, 0);
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;
}
