#include <bits/stdc++.h>
#define N 1000001
using namespace std;
typedef long long ll;
const ll INF = 1e18, MOD = 1e9 + 7, MOD2 = 1e6 + 3;
int n, l[N], r[N];
int ind[2 * N];
bitset<2*N> u, col;
struct SegTree {
ll t[8 * N], start;
bool mx;
void build (ll n, bool mx) {
this -> mx = mx;
start = 1;
while (start < n) start <<= 1;
if (mx) fill (t, t + 2 * start, -INF);
else fill (t, t + 2 * start, INF);
}
void update (ll x, ll d) {
x += start;
t[x] = d;
x >>= 1;
while (x) {
if (mx) t[x] = max (t[2 * x], t[2 * x + 1]);
else t[x] = min (t[2 * x], t[2 * x + 1]);
x >>= 1;
}
}
ll get_max (ll l, ll r) {
l += start, r += start + 1;
ll mx = -INF;
while (l < r) {
if (l & 1) mx = max (mx, t[l++]);
if (r & 1) mx = max (mx, t[--r]);
l >>= 1, r >>= 1;
}
return mx;
}
ll get_min (ll l, ll r) {
l += start, r += start + 1;
ll mn = INF;
while (l < r) {
if (l & 1) mn = min (mn, t[l++]);
if (r & 1) mn = min (mn, t[--r]);
l >>= 1, r >>= 1;
}
return mn;
}
} t_l, t_r;
bool check (vector <pair <int, int> > v){
sort (v.begin(), v.end());
stack < pair <int, int> > st;
for(ll i = 0; i < v.size (); i++){
while(!st.empty () && st.top ().second < v[i].first)
st.pop ();
if(!st.empty () && st.top().second < v[i].second)
return 0;
st.push (v[i]);
}
return 1;
}
void dfs (ll x, ll c) {
col[x] = c, u[x] = 1;
t_l.update (r[x], INF);
t_r.update (l[x], -INF);
while (true) {
ll t = t_r.get_max (l[x] + 1, r[x] - 1);
if(t <= r[x]) break;
ll to = ind[t];
dfs (to, !c);
}
while (true) {
ll t = t_l.get_min (l[x] + 1, r[x] - 1);
if(l[x] <= t) break;
ll to = ind[t];
dfs (to, !c);
}
}
int main () {
cin >> n;
t_l.build (2 * n, false);
t_r.build (2 * n, true);
memset (ind, -1, sizeof (ind));
for (ll i = 0; i < n; i++) {
cin >> l[i] >> r[i];
l[i]--, r[i]--;
ind[l[i]] = ind[r[i]] = i;
t_l.update (r[i], l[i]);
t_r.update (l[i], r[i]);
}
ll ans = 1;
for (ll i = 0; i < 2 * n; i++) {
if (ind[i] >= 0 && !u[ind[i]]) {
ans = 2 * ans % MOD;
dfs (ind[i], 0);
}
}
vector < pair <int, int> > a, b;
for (ll i = 0; i < n; i++) {
if (col[i]) a.push_back ({l[i], r[i]});
else b.push_back ({l[i], r[i]});
}
if (!check (a) || !check (b)) {
cout << 0;
return 0;
}
cout << ans << endl;
}
