#include<bits/stdc++.h>
using namespace std;
#define int long long
struct dsu {
int n, cc;
vector<int> r, s;
dsu(int n) {
this->n=n; cc=n;
r.reserve(n+1);
for (int i = 1; i <= n; ++i) r[i]=i;
s.assign(n+1, 1);
}
int find(int a) {
if (a==r[a]) return a;
return r[a]=find(r[a]);
}
bool unite(int a, int b) {
if (b==-1) return false;
a=find(a), b=find(b);
if (a==b) return true;
if (s[a]<s[b]) swap(a, b);
r[b]=a; s[a]+=s[b]; cc--;
return false;
}
};
int exp(int a, int b, int mod) {
int x=1;
while (b) {
if (b%2) x=(x*a)%mod;
a=(a*a)%mod; b/=2;
} return x;
}
signed main() {
cin.tie(0)->sync_with_stdio(false);
int n;
cin >> n;
set<pair<int, int>> s;
vector<int> a(n), b(n);
for (int i = 0; i < n; ++i) {
cin >> a[i] >> b[i];
s.insert({a[i], i+1});
s.insert({b[i], -i-1});
}
dsu uf(n);
vector<int> c, p(n+1);
for (auto i = s.begin(); i != s.end(); ++i) {
auto [t, j] = *i;
if (j>0) {
p[j]=c.size();
c.push_back(j);
} else {
for (int k = p[-j]+1; k < c.size(); ++k) {
if (uf.unite(-j, c[k])) { cout << "0\n"; return 0; }
} c[p[-j]]=-1;
}
}
cout << exp(2, uf.cc, 1e9+7) << '\n';
return 0;
}
