/**
_ _ __ _ _ _ _ _ _
|a ||t ||o d | |o |
| __ _| | _ | __| _ |
| __ |/_ | __ /__\ / _\|
**/
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N_MAX = 1000000;
const int MOD = (int) 1e9 + 7;
int N;
int L[N_MAX + 2], R[N_MAX + 2];
struct SegInfo {
vector <int> byL, byR;
};
SegInfo seg_tree[N_MAX * 8 + 2];
void add_L (int node, int l, int r, int i) {
seg_tree[node].byL.push_back(i);
if (l == r) {
return;
}
int mid = (l + r) / 2;
int left = node * 2, right = node * 2 + 1;
if (R[i] <= mid) {
add_L(left, l, mid, i);
} else {
add_L(right, mid + 1, r, i);
}
}
void add_L (int i) {
add_L(1, 1, N * 2, i);
}
void add_R (int node, int l, int r, int i) {
seg_tree[node].byR.push_back(i);
if (l == r) {
return;
}
int mid = (l + r) / 2;
int left = node * 2, right = node * 2 + 1;
if (L[i] <= mid) {
add_R(left, l, mid, i);
} else {
add_R(right, mid + 1, r, i);
}
}
void add_R (int i) {
add_R(1, 1, N * 2, i);
}
int order[N_MAX + 2];
int color[N_MAX + 2];
int find_L (int node, int l, int r, int i) {
if (L[i] <= l && r <= R[i]) {
while (seg_tree[node].byL.empty() == false && color[seg_tree[node].byL.back()] != 0) {
seg_tree[node].byL.pop_back();
}
if (seg_tree[node].byL.empty() == false && L[seg_tree[node].byL.back()] < L[i]) {
return seg_tree[node].byL.back();
} else {
return 0;
}
}
int mid = (l + r) / 2;
int left = node * 2, right = node * 2 + 1;
if (L[i] <= mid) {
int j = find_L(left, l, mid, i);
if (j != 0) {
return j;
}
}
if (mid + 1 <= R[i]) {
int j = find_L(right, mid + 1, r, i);
if (j != 0) {
return j;
}
}
return 0;
}
int find_L (int i) {
return find_L(1, 1, N * 2, i);
}
int find_R (int node, int l, int r, int i) {
if (L[i] <= l && r <= R[i]) {
while (seg_tree[node].byR.empty() == false && color[seg_tree[node].byR.back()] != 0) {
seg_tree[node].byR.pop_back();
}
if (seg_tree[node].byR.empty() == false && R[i] < R[seg_tree[node].byR.back()]) {
return seg_tree[node].byR.back();
} else {
return 0;
}
}
int mid = (l + r) / 2;
int left = node * 2, right = node * 2 + 1;
if (L[i] <= mid) {
int j = find_R(left, l, mid, i);
if (j != 0) {
return j;
}
}
if (mid + 1 <= R[i]) {
int j = find_R(right, mid + 1, r, i);
if (j != 0) {
return j;
}
}
return 0;
}
int find_R (int i) {
return find_R(1, 1, N * 2, i);
}
void dfs (int i) {
int j;
while (j = find_L(i)) {
color[j] = 3 - color[i];
dfs(j);
}
while (j = find_R(i)) {
color[j] = 3 - color[i];
dfs(j);
}
}
int which[N_MAX * 2 + 2];
int main () {
ios_base::sync_with_stdio(false);
cin.tie(0);
cin >> N;
for (int i = 1; i <= N; i++) {
cin >> L[i] >> R[i];
}
iota(order + 1, order + N + 1, 1);
sort(order + 1, order + N + 1, [&] (const int &i, const int &j) {
return L[i] > L[j];
});
for (int i = 1; i <= N; i++) {
add_L(order[i]);
}
sort(order + 1, order + N + 1, [&] (const int &i, const int &j) {
return R[i] < R[j];
});
for (int i = 1; i <= N; i++) {
add_R(order[i]);
}
int answer = 1;
for (int i = 1; i <= N; i++) {
if (color[i] == 0) {
color[i] = 1;
dfs(i);
answer = answer * 2 % MOD;
}
}
for (int i = 1; i <= N; i++) {
which[L[i]] = which[R[i]] = i;
}
vector <int> st[3];
for (int i = 1; i <= N * 2; i++) {
if (i == L[which[i]]) {
st[color[which[i]]].push_back(which[i]);
} else {
if (st[color[which[i]]].back() != which[i]) {
cout << 0 << "\n";
exit(0);
}
st[color[which[i]]].pop_back();
}
}
cout << answer << "\n";
return 0;
}
