// oooo
/*
har chi delet mikhad bebar ~
gitar o ba khodet nabar! ~
;Amoo_Hasan;
*/
#include<bits/stdc++.h>
//#pragma GCC optimize("O3,no-stack-protector,unroll-loops")
//#pragma GCC target("avx2,fma")
using namespace std;
typedef long long ll;
typedef long double ld;
#define Sz(x) int((x).size())
#define All(x) (x).begin(), (x).end()
constexpr ll inf = 1e18, N = 1e6 + 10, mod = 1e9 + 7, pr = 1000696969;
int n, a[N], b[N];
bool mark[N], color[N];
struct node {
int pos;
} x[N << 2];
void change(int l, int r, int ind, int pos, int v) {
if(r - l < 2) {
x[v].pos = pos;
return;
}
int mid = (l + r) / 2;
if(ind < mid) change(l, mid, ind, pos, 2 * v);
else change(mid, r, ind, pos, 2 * v + 1);
if(b[x[2 * v].pos] > b[x[2 * v + 1].pos]) x[v].pos = x[2 * v].pos;
else x[v].pos = x[2 * v + 1].pos;
}
int get(int l, int r, int s, int e, int v) {
if(r <= s || l >= e) return 0;
if(l >= s && r <= e) {
return x[v].pos;
}
int mid = (l + r) >> 1;
int pl = get(l, mid, s, e, 2 * v), pr = get(mid, r, s, e, 2 * v + 1);
if(b[pl] >= b[pr]) return pl;
else return pr;
}
void DFS(int x) {
mark[x] = 1;
change(1, 2 * n + 1, a[x], 0, 1);
while(true) {
int ans = get(1, 2 * n + 1, a[x] + 1, b[x], 1);
if(b[ans] <= b[x]) {
break;
}
color[ans] = 1 - color[x];
DFS(ans);
}
}
bool cmp(pair<int, int> p1, pair<int, int> p2) {
int cnt1 = 0, cnt2 = 0;
if(p1.second == 0) cnt1 = a[p1.first];
else cnt1 = b[p1.first];
if(p2.second == 0) cnt2 = a[p2.first];
else cnt2 = b[p2.first];
return cnt1 < cnt2;
}
ll poww(ll x, int y) {
ll res = 1;
for(; y; y /= 2, x = x * x % mod)
if(y & 1) {
res = res * x % mod;
}
return res;
}
int main() {
ios :: sync_with_stdio(0), cin.tie(0);
cin >>n;
for(int i = 1; i <= n; i++) {
cin >>a[i] >>b[i];
change(1, 2 * n + 1, a[i], i, 1);
}
int colorcnt = 0;
for(int i = 1; i <= n; i++) {
if(mark[i]) continue;
DFS(i);
colorcnt++;
}
vector<int> c[2]; vector<pair<int, int> > vc;
for(int i = 1; i <= n; i++) {
vc.push_back({i, 0});
vc.push_back({i, 1});
}
sort(All(vc), cmp);
for(auto i : vc) {
if(i.second == 0) c[color[i.first]].push_back(i.first);
else {
if(c[color[i.first]].empty() || c[color[i.first]].back() != i.first) {
return cout<<0, 0;
}
c[color[i.first]].pop_back();
}
}
cout<<poww(2, colorcnt);
return 0;
}
