#include <bits/stdc++.h>
#pragma gcc("O3, unroll-loops")
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define pb push_back
#define FIO ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)
using namespace std;
typedef long long ll;
typedef pair <int, int> pii;
const int N = 1e6 + 7, ofs = (1 << 21), mod = 1e9 + 7;
int n, E;
int l[N], r[N], par[N], siz[N], bio[N], col[N];
pii t[2*ofs];
vector <int> no[N], adj[N];
void add(int x, int y) {
x += ofs;
t[x] = {y, y};
while (x /= 2) t[x] = {max(t[2*x].F, t[2*x+1].F), min(t[2*x].S, t[2*x+1].S)};
}
pii get(int x, int a, int b, int lo = 0, int hi = ofs-1) {
if (b < lo || hi < a) return {-1, n};
if (a <= lo && hi <= b) return t[x];
int mid = (lo + hi) / 2;
pii p1 = get(2*x, a, b, lo, mid), p2 = get(2*x+1, a, b, mid+1, hi);
return {max(p1.F, p2.F), min(p1.S, p2.S)};
}
int find(int x) {return (x == par[x]) ? x : (par[x] = find(par[x]));}
void unite(int x, int y) {
x = find(x); y = find(y);
if (x == y) return;
if (siz[x] < siz[y]) swap(x, y);
siz[x] += siz[y];
par[y] = x;
for (auto z : no[y]) {
add(r[z], x);
no[x].pb(z);
}
}
void dfs(int x) {
bio[x] = 1;
for (auto y : adj[x]) {
if (bio[y]) {
if (col[x] == col[y]) E = 1;
continue;
}
col[y] = col[x] ^ 1;
dfs(y);
}
}
int madd(int x, int y) {return (x+y < mod) ? (x+y) : (x+y-mod);}
int mul(int x, int y) {return (ll)x*y%mod;}
int main () {
FIO;
cin >> n;
for (int i = 0; i < 2*ofs; i++) t[i] = {-1, n};
vector <pii> v;
for (int i = 0; i < n; i++) {
cin >> l[i] >> r[i]; l[i]--; r[i]--;
par[i] = i;
siz[i] = 1;
v.pb({l[i], i});
no[i] = {i};
}
sort(all(v));
vector <pii> ed;
for (int i = 0; i < n; i++) {
int x = v[i].S;
pii o = get(1, l[x], r[x]);
if (o.F != -1 && o.F != o.S) {
while (o.F != o.S) {
unite(o.F, o.S);
o = get(1, l[x], r[x]);
}
}
if (o.F != -1) {
ed.pb({o.F, x});
}
add(r[x], x);
}
for (int i = 0; i < ed.size(); i++) {
int x = find(ed[i].F), y = find(ed[i].S);
adj[x].pb(y);
adj[y].pb(x);
}
int res = 1;
for (int i = 0; i < n; i++) {
int x = find(i);
if (bio[x]) continue;
res = mul(res, 2);
dfs(x);
}
cout << ((E) ? 0 : res);
return 0;
}
