#include <cstdio>
#include <algorithm>
#include <vector>
#include <functional>
#include <queue>
#include <cstring>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> ii;
#define SZ(x) ((int)x.size())
const int N = (int)1e6+5;
const int base = (int)1e9+7;
int n, vis[N], lo[2][N], hi[2][N], b[2][N];
ii tree[2][1 << 21], a[2][N];
void merge_tree_min(ii tr[], int root, int lf, int rt) {
if (tr[lf].first > tr[rt].first)
tr[root] = tr[rt];
else tr[root] = tr[lf];
}
void merge_tree_max(ii tr[], int root, int lf, int rt) {
if (tr[lf].first < tr[rt].first)
tr[root] = tr[rt];
else tr[root] = tr[lf];
}
void build(int k, int l, int r) {
if (l > r) return;
if (l == r) {
tree[0][k] = ii(a[0][l].second, l);
tree[1][k] = ii(a[1][l].second, l);
return;
}
int mid = (l + r) >> 1;
build(k << 1, l, mid);
build(k << 1 | 1, mid + 1, r);
merge_tree_max(tree[0], k, k << 1, k << 1 | 1);
merge_tree_min(tree[1], k, k << 1, k << 1 | 1);
}
void _remove_max(int k, int l, int r, int pos) {
if (l > r || l > pos || r < pos) return;
if (l == r && l == pos) {
tree[0][k] = ii(0, 0);
return;
}
int mid = (l + r) >> 1;
_remove_max(k << 1, l, mid, pos);
_remove_max(k << 1 | 1, mid + 1, r, pos);
merge_tree_max(tree[0], k, k << 1, k << 1 | 1);
}
void _remove_min(int k, int l, int r, int pos) {
if (l > r || l > pos || r < pos) return;
if (l == r && l == pos) {
tree[1][k] = ii(2*n+1, 0);
return;
}
int mid = (l + r) >> 1;
_remove_min(k << 1, l, mid, pos);
_remove_min(k << 1 | 1, mid + 1, r, pos);
merge_tree_min(tree[1], k, k << 1, k << 1 | 1);
}
ii query_max(ii tr[], int k, int l, int r, int L, int R) {
if (l > r || l > R || r < L) return ii(0, 0);
if (L <= l && r <= R) return tr[k];
int mid = (l + r) >> 1;
ii lf = query_max(tr, k << 1, l, mid, L, R);
ii rt = query_max(tr, k << 1 | 1, mid + 1, r, L, R);
if (lf.first < rt.first) return rt;
return lf;
}
ii query_min(ii tr[], int k, int l, int r, int L, int R) {
if (l > r || l > R || r < L) return ii(2*n+1, 0);
if (L <= l && r <= R) return tr[k];
int mid = (l + r) >> 1;
ii lf = query_min(tr, k << 1, l, mid, L, R);
ii rt = query_min(tr, k << 1 | 1, mid + 1, r, L, R);
if (lf.first > rt.first) return rt;
return lf;
}
int bit[2*N];
void update_bit(int idx, int val) {
for (; idx <= 2*n; idx += idx & -idx)
bit[idx] += val;
}
int read_bit(int idx) {
int ans = 0;
for (; idx > 0; idx -= idx & -idx)
ans += bit[idx];
return ans;
}
bool check(int id) {
memset(bit, 0, sizeof(bit));
vector<ii> c;
for (int i = 1; i <= n; ++i) if (vis[i] == id)
c.push_back(a[0][i]);
for (int i = 0; i < SZ(c); ++i) {
int tmp = read_bit(c[i].second) - read_bit(c[i].first);
if (tmp > 0) return false;
update_bit(c[i].second, 1);
}
return true;
}
int main() {
scanf("%d", &n);
for (int i = 1; i <= n; ++i) scanf("%d%d", &a[0][i].first, &a[0][i].second), a[1][i] = a[0][i];
sort(a[0] + 1, a[0] + n + 1);
for (int i = 1; i <= n; ++i) {
lo[0][i] = i;
hi[0][i] = upper_bound(a[0] + i, a[0] + n + 1, ii(a[0][i].second, 0)) - a[0] - 1;
swap(a[1][i].first, a[1][i].second);
}
sort(a[1] + 1, a[1] + n + 1);
for (int i = 1; i <= n; ++i) {
hi[1][i] = i;
lo[1][i] = lower_bound(a[1] + 1, a[1] + i, ii(a[1][i].second, 0)) - a[1];
b[1][i] = lower_bound(a[0] + 1, a[0] + n + 1, ii(a[1][i].second, 0)) - a[0];
b[0][i] = lower_bound(a[1] + 1, a[1] + n + 1, ii(a[0][i].second, 0)) - a[1];
}
build(1, 1, n);
int ans = 1;
for (int i = 1; i <= n; ++i) if (!vis[i]) {
queue<int> q;
q.push(i);
vis[i] = 1;
_remove_max(1, 1, n, i);
_remove_min(1, 1, n, b[0][i]);
while (SZ(q)) {
int u = q.front(); q.pop();
ii tmp = query_max(tree[0], 1, 1, n, lo[0][u], hi[0][u]);
while (tmp.first > a[0][u].second) {
vis[tmp.second] = 3 - vis[u];
q.push(tmp.second);
_remove_max(1, 1, n, tmp.second);
_remove_min(1, 1, n, b[0][tmp.second]);
tmp = query_max(tree[0], 1, 1, n, lo[0][u], hi[0][u]);
}
int u2 = b[0][u];
tmp = query_min(tree[1], 1, 1, n, lo[1][u2], hi[1][u2]);
while (tmp.first < a[1][u2].second) {
vis[b[1][tmp.second]] = 3 - vis[u];
q.push(b[1][tmp.second]);
_remove_min(1, 1, n, tmp.second);
_remove_max(1, 1, n, b[1][tmp.second]);
tmp = query_min(tree[1], 1, 1, n, lo[1][u2], hi[1][u2]);
}
}
ans = ans * 2 % base;
}
if (check(1) && check(2)) printf("%d", ans);
else printf("0");
return 0;
}
