//Challenge: Accepted
#include <iostream>
#include <algorithm>
#include <utility>
#include <vector>
#include <map>
#include <set>
#include <stack>
#define ll long long
#define maxn 2005
#define mod 1000000007
#define pii pair<int, int>
#define ff first
#define ss second
using namespace std;
pii a[maxn];
bool adj[maxn][maxn], found[maxn];
int col[maxn];
int poss = 1;
void dfs(int n, int c) {
found[n] = 1;
col[n] = c;
for (int v = 0;v < maxn;v++) {
if (!adj[n][v]) continue;
if (!found[v]) {
found[v] = 1;
dfs(v, 3 - c);
} else if (col[n] == col[v]) {
poss = 0;
return;
}
}
}
int main() {
ios_base::sync_with_stdio(0);cin.tie(0);
int n;
cin >> n;
for (int i = 0;i < n;i++) cin >> a[i].ff >> a[i].ss;
sort(a, a + n);
for (int i = 0;i < n;i++) {
for (int j = i + 1;j < n;j++) {
if (a[j].ff < a[i].ss && a[j].ss > a[i].ss) {
adj[i][j] = adj[j][i] = 1;
}
}
}
ll ans = 1;
for (int i = 0;i < n;i++) {
if (!found[i]) {
ans = (ans * 2) % mod;
dfs(i, 1);
}
}
cout << (poss ? ans : 0) << "\n";
}
