#include <bits/stdc++.h>
using namespace std;
#define FOR(i, a, b) for(int i = a; i <= b; i++)
#define FOD(i, a, b) for(int i = a; i >= b; i--)
#define fi first
#define se second
#define ll long long
#define db double
#define ii pair<int,int>
#define pb push_back
#define MASK(i) (1LL << i)
#define sq(i) (1LL * (i) * (i))
#define task "task"
const ll INF = 1e18;
const int inf = 1e9;
const int N = 1e6 + 4;
const int mod = 1e9 + 7;
int n, res = 1;
ii a[N];
int idx[2 * N], c[N], cnt[2], save[N][2];
struct SmtMax {
int mx[8 * N];
void init() {
FOR(i, 1, 8 * n) mx[i] = -1;
}
void upd(int id, int l, int r, int pos, int d) {
assert(l <= r);
if(l == r) {
mx[id] = d;
return;
}
int mid = l + r >> 1;
if(pos <= mid) upd(id << 1, l, mid, pos, d);
else upd(id << 1 | 1, mid + 1, r, pos, d);
mx[id] = max(mx[id << 1], mx[id << 1 | 1]);
}
int get(int id, int l, int r, int u, int v) {
if(l > v || r < u || u > v) return -1;
if(l >= u && r <= v) return mx[id];
int mid = l + r >> 1;
return max(get(id << 1, l, mid, u, v), get(id << 1 | 1, mid + 1, r, u, v));
}
} smtmax;
struct SmtMin {
int mn[8 * N];
void init() {
FOR(i, 1, 8 * n) mn[i] = 2 * n + 1;
}
void upd(int id, int l, int r, int pos, int d) {
assert(l <= r);
if(l == r) {
mn[id] = d;
return;
}
int mid = l + r >> 1;
if(pos <= mid) upd(id << 1, l, mid, pos, d);
else upd(id << 1 | 1, mid + 1, r, pos, d);
mn[id] = min(mn[id << 1], mn[id << 1 | 1]);
}
int get(int id, int l, int r, int u, int v) {
if(l > v || r < u || u > v) return 2 * n + 1;
if(l >= u && r <= v) return mn[id];
int mid = l + r >> 1;
return min(get(id << 1, l, mid, u, v), get(id << 1 | 1, mid + 1, r, u, v));
}
} smtmin;
void dfs(int u, int col) {
c[u] = col;
smtmax.upd(1, 1, 2 * n, a[u].fi, -1);
smtmin.upd(1, 1, 2 * n, a[u].se, 2 * n + 1);
while(true) {
int p = smtmax.get(1, 1, 2 * n, a[u].fi + 1, a[u].se - 1);
if(p <= a[u].se) break;
dfs(idx[p], col ^ 1);
}
while(true) {
int p = smtmin.get(1, 1, 2 * n, a[u].fi + 1, a[u].se - 1);
if(p >= a[u].fi) break;
dfs(idx[p], col ^ 1);
}
}
signed main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n;
FOR(i, 1, n) {
cin >> a[i].fi >> a[i].se;
idx[a[i].fi] = i;
idx[a[i].se] = i;
}
smtmax.init();
smtmin.init();
FOR(i, 1, n) {
smtmax.upd(1, 1, 2 * n, a[i].fi, a[i].se);
smtmin.upd(1, 1, 2 * n, a[i].se, a[i].fi);
c[i] = -1;
}
FOR(i, 1, n) if(c[i] == -1) {
dfs(i, 0);
(res *= 2) %= mod;
}
vector<ii> ev;
FOR(i, 1, n) {
save[i][0] = save[i][1] = -1;
ev.pb({a[i].fi, i});
ev.pb({a[i].se, i});
}
sort(ev.begin(), ev.end());
for(ii x : ev) {
int p = x.fi;
int id = x.se;
if(save[id][0] == -1) {
save[id][0] = cnt[0];
save[id][1] = cnt[1];
cnt[c[id]]++;
}
else {
if(cnt[c[id]] - save[id][c[id]] > 1) {
cout << 0 << '\n';
return 0;
}
cnt[c[id]]--;
}
}
cout << res << '\n';
}
