#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int mod = 1e9 + 7;
int n, l[1001001], r[1001001], z[2002002], p[2002002];
int find(int x) { return x == p[x] ? x : p[x] = find(p[x]); }
int merge(int x, int y) {
p[find(x+n)] = find(y);
p[find(y+n)] = find(x);
return find(x) == find(y);
}
int main() {
cin.tie(0)->sync_with_stdio(0);
cin >> n;
for(int i=1;i<=n;i++) {
cin >> l[i] >> r[i];
z[l[i]] = i, z[r[i]] = -i;
}
map<int, int> mp;
iota(p+1, p+1+n+n, 1);
for(int i=1;i<=n+n;i++) {
if(z[i] > 0) {
mp[i] = z[i];
} else {
int u = -z[i];
auto it = mp.find(l[u]);
it = mp.erase(it);
while(it != mp.end()) {
if(merge(u, it->second)) return cout << 0, 0;
it++;
}
}
}
for(int i=1;i<=n;i++) p[find(i+n)] = find(i);
int ans = 1;
for(int i=1;i<=n;i++) if(i == find(i)) ans = ans*2%mod;
cout << ans;
}
