/* In the name of God, aka Allah */
// let this be mytemp.cpp
#include<bits/stdc++.h>
using namespace std;
#define F first
#define S second
#define endl '\n'
#define mk make_pair
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int mod = 1e9 + 7;
int add(int a, int b) {
a += b;
if (a >= mod) a -= mod;
if (a < 0) a += mod;
return a;
}
int mul(int a, int b) {
return 1ll*a*b%mod;
}
int pw(int a, int b) {
int out = 1;
while (b) {
if (b&1) out = mul(out, a);
a = mul(a,a);
b>>=1;
}
return out;
}
const int inf = 1e9 + 50;
const int N = 2e6 + 50;
int n, id[N], c[N];
pii P[N];
pii seg[N<<2][2];
vector<int> A[2];
void build(int u=1, int tl=1, int tr=2*n) {
if (tl == tr) {
seg[u][0] = {P[id[tl]].F, id[tl]}, seg[u][1] = {P[id[tl]].S, id[tl]};
return;
}
int md = (tl+tr)/2;
int lc = u<<1;
int rc = u<<1|1;
build(lc, tl, md), build(rc, md+1, tr);
seg[u][0] = min(seg[lc][0], seg[rc][0]);
seg[u][1] = max(seg[lc][1], seg[rc][1]);
}
pii get(int c, int l, int r, int u=1, int tl=1, int tr=2*n) {
if (r < tl || tr < l) return {(c? -inf:inf), 0};
if (l <= tl && tr <= r) return seg[u][c];
int md = (tl+tr)/2;
int lc = u<<1;
int rc = u<<1|1;
pii A = get(c, l, r, lc, tl, md), B = get(c, l, r, rc, md+1, tr);
return (c? max(A,B) : min(A,B));
}
void upd(int id, int u=1, int tl=1, int tr=2*n) {
if (id < tl || tr < id) return;
if (tl == tr) {
seg[u][0] = {inf, 0};
seg[u][1] = {-inf, 0};
return;
}
int md = (tl+tr)/2;
int lc = u<<1;
int rc = u<<1|1;
upd(id, lc, tl, md), upd(id, rc, md+1, tr);
seg[u][0] = min(seg[lc][0], seg[rc][0]);
seg[u][1] = max(seg[lc][1], seg[rc][1]);
}
void pop(int u) {
upd(P[u].F), upd(P[u].S);
}
void solve() {
cin >> n;
for (int i = 1; i <= n; i++) {
int l, r;
cin >> l >> r;
id[l] = id[r] = i;
P[i] = {l, r};
}
for (int u = 1; u <= n; u++) c[u] = -1;
build();
queue<int> q;
int t = 0;
for (int i = 1; i <= 2*n; i++) {
if (c[id[i]] >= 0) continue;
t++;
c[id[i]] = 0;
q.push(id[i]);
pop(id[i]);
while(q.size()) {
int u = q.front();
q.pop();
pii x = get(0, P[u].S, 2*n);
while (x.F < P[u].S) {
int v = x.S;
c[v] = 1-c[u];
q.push(v);
pop(v);
x = get(0, P[u].S, 2*n);
}
x = get(1, 1, P[u].F);
while (x.F > P[u].F) {
int v = x.S;
c[v] = 1-c[u];
q.push(v);
pop(v);
x = get(1, 1, P[u].F);
}
}
}
bool flg = 1;
for (int i = 1; i <= 2*n; i++) {
int u = id[i];
if (P[u].F == i) A[c[u]].push_back(u);
else {
if (A[c[u]].back() != u) flg = 0;
A[c[u]].pop_back();
}
}
cout << (flg? pw(2, t) : 0) << endl;
}
int main() {
ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
solve();
return 0;
}
