#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef pair<int,int> ii;
const ll M = 1e9+7;
class U {
private:
vector<set<int>> cont[2];
vi p,sz;
int n,nc;
public:
U(vector<ii> w) {
n = w.size();
cont[0].assign(n,set<int>());
cont[1].assign(n,set<int>());
nc = n;
sz.assign(n,1);
for(int i=0;i<n;i++) {
p.push_back(i);
cont[0][i].insert(w[i].second);
}
}
int find(int a) {
if(a == p[a]) {return a;}
return p[a] = find(p[a]);
}
bool same(int a, int b) {return find(a) == find(b);}
bool un(int a, int b, int u, int v) {
if(same(a,b)) {return false;}
int x = find(a),y = find(b);
int par = (cont[0][x].count(u))^(cont[1][y].count(v));
if(sz[x] < sz[y]) {swap(x,y);}
for(int i=0;i<2;i++) {
cont[i][x].insert(cont[i^par][y].begin(),cont[i^par][y].end());
cont[i^par][y].clear();
}
p[y] = x;
sz[x] += sz[y];
nc--;
return true;
}
int num() {
return nc;
}
ii pop(int u) {
u = find(u);
int res[2] = {1<<29,1<<29};
for(int i=0;i<2;i++) {
if(cont[i][u].size() > 0) {
res[i] = *cont[i][u].begin();
}
}
int idx = res[0] > res[1];
if(cont[idx][u].size() > 0) {
cont[idx][u].erase(cont[idx][u].begin());
res[idx] = (cont[idx][u].size() > 0?*cont[idx][u].begin():1<<29);
}
return {res[0],res[1]};
}
ll dup(int u) {
u = find(u);
int res = -1e9;
for(int i=0;i<2;i++) {
if(cont[i][u].empty()) {
return 1e9;
}
res = max(res,*cont[i][u].begin());
}
return res;
}
};
int main() {
ios::sync_with_stdio(0);cin.tie(0);
int n;
cin >> n;
vector<ii> w;
vi rm(2*n,-1);
for(int i=0;i<n;i++) {
int a,b;
cin >> a >> b;
a--;b--;
w.emplace_back(a,b);
}
sort(w.begin(),w.end());
for(int i=0;i<n;i++) {
rm[w[i].first] = rm[w[i].second] = i;
}
U bs(w);
map<int,int> lu;
int rop = 0;
ll res = 1;
for(int i=0;i<w.size();i++) {
ii va = w[i];
while(!lu.empty() && lu.begin()->first < va.first) {
int id = bs.find(lu.begin()->second);
lu.erase(lu.begin());
ii nx = {-1,-1};
while(min(nx.first,nx.second) < va.first) {
nx = bs.pop(id);
}
int bu[2] = {nx.first,nx.second};
lu[min(nx.first,nx.second)] = id;
}
if(!lu.empty() && lu.begin()->first < va.second) {
ll mv = lu.begin()->first;
while(!lu.empty() && lu.begin()->first < va.second) {
ll ko = lu.begin()->second;
ll kv = lu.begin()->first;
if(bs.dup(ko) < va.second) {
res = 0;
}
bs.un(ko,i,kv,va.second);
lu.erase(lu.begin());
}
lu[mv] = i;
} else {
lu[va.second] = i;
}
}
ll lol = bs.num();
for(int i=0;i<lol;i++) {
res *= 2;
if(res >= M) {res -= M;}
}
cout << res << '\n';
}
