#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const ll MOD = 1e9 + 7;
const int N = 1000001;
ll pw[N];
int col[N], l[N], r[N], b[2 * N];
int odd[2 * N], even[2 * N];
void update(int v, int w, int p) {
if (!p) for (int i = v;i < 2 * N - 1;i += i & -i) odd[i] += w;
else for (int i = v;i < 2 * N - 1;i += i & -i) even[i] += w;
}
int query(int v, int p) {
int ans = 0;
if (!p) for (int i = v;i > 0;i -= i & -i) ans += odd[i];
else for (int i = v;i > 0;i -= i & -i) ans += even[i];
return ans;
}
vector<int> adj[N];
bool dfs(int v, int c = 1) {
if (col[v]) return c == col[v];
col[v] = c;
for (auto& x : adj[v]) {
if (!dfs(x, 3 - c)) return false;
}
return true;
}
int main() {
cin.tie(nullptr)->sync_with_stdio(false);
pw[0] = 1;
for (int i = 1;i <= 1000000;i++) pw[i] = pw[i - 1] * 2 % MOD;
int n;
cin >> n;
for (int i = 1;i <= n;i++) {
cin >> l[i] >> r[i];
b[r[i]] = l[i];
}
for (int i = 1;i <= n;i++) {
for (int j = i + 1;j <= n;j++) {
int ii = i, jj = j;
if (l[i] > l[j]) swap(ii, jj);
if (l[jj] < r[ii] && r[ii] < r[jj]) {
adj[i].push_back(j);
adj[j].push_back(i);
}
}
}
for (int i = 1;i <= n;i++) {
if (!col[i]) {
if (!dfs(i)) {
cout << 0 << '\n';
return 0;
}
}
}
int cnt = 0;
for (int i = 1;i <= 2 * n;i++) {
if (!b[i]) continue;
if (!query(b[i], 0)) cnt++;
update(b[i], 1, 0);
update(i + 1, -1, 0);
}
cout << pw[cnt] << '\n';
return 0;
}
