#include <bits/stdc++.h>
using namespace std;
#ifdef ngu
#include "debug.h"
#else
#define debug(...) 42
#endif
using ll = long long;
const int N = 1e6 + 5, MOD = 1e9 + 7, inf = 1e9;
int n;
int c[N], a[N], b[N];
struct Segtree {
array<int, 2> s[8 * N];
void upd(int i, array<int, 2> v) {
int id = 1, l = 1, r = 2 * n;
while (l ^ r) {
int md = (l + r) / 2;
id *= 2;
if (i <= md) {
r = md;
} else {
l = md + 1;
id += 1;
}
}
s[id] = v;
while (id > 1) {
id /= 2;
s[id] = max(s[id * 2], s[id * 2 + 1]);
}
}
array<int, 2> get(int id, int l, int r, int u, int v) {
if (u <= l && r <= v) {
return s[id];
}
int md = (l + r) / 2;
if (u <= md && md < v) {
return max(get(id * 2, l, md, u, v), get(id * 2 + 1, md + 1, r, u, v));
}
if (md < u) {
return get(id * 2 + 1, md + 1, r, u, v);
}
return get(id * 2, l, md, u, v);
}
array<int, 2> get(int l, int r) {
return get(1, 1, 2 * n, l, r);
}
};
Segtree A, B;
void dfs(int u) {
A.upd(a[u], {-inf, -1});
B.upd(b[u], {-inf, -1});
array<int, 2> v;
while ((v = A.get(a[u], b[u]))[0] > b[u]) {
c[v[1]] = c[u] ^ 1;
dfs(v[1]);
}
while (-(v = B.get(a[u], b[u]))[0] < a[u]) {
c[v[1]] = c[u] ^ 1;
dfs(v[1]);
}
}
void reset() {
for (int i = 1; i <= 2 * n; ++i) {
A.upd(i, {-inf, -1});
B.upd(i, {-inf, -1});
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
#ifdef ngu
freopen("test.inp", "r", stdin);
freopen("test.out", "w", stdout);
#endif
cin >> n;
reset();
for (int i = 1; i <= n; ++i) {
cin >> a[i] >> b[i];
c[i] = -1;
A.upd(a[i], {b[i], i});
B.upd(b[i], {-a[i], i});
}
int res = 1;
for (int i = 1; i <= n; ++i) {
if (c[i] == -1) {
c[i] = 0;
dfs(i);
res = ll(res) * 2 % MOD;
}
}
reset();
for (int i = 1; i <= n; ++i) {
if (c[i] == 0) {
A.upd(a[i], {b[i], i});
B.upd(b[i], {-a[i], i});
if (A.get(a[i], b[i])[0] > b[i] || -B.get(a[i], b[i])[0] < a[i]) {
cout << 0;
exit(0);
}
}
}
reset();
for (int i = 1; i <= n; ++i) {
if (c[i] == 1) {
A.upd(a[i], {b[i], i});
B.upd(b[i], {-a[i], i});
if (A.get(a[i], b[i])[0] > b[i] || -B.get(a[i], b[i])[0] < a[i]) {
cout << 0;
exit(0);
}
}
}
cout << res;
}
