#include <bits/stdc++.h>
using namespace std;
int main() {
int n;
cin >> n;
int a[n], b[n], pref[2*n+1], cur[2*n];
bool vis[n];
vector<int> adj[n];
memset(pref,0,sizeof(pref));
for(int i=0;i<n;i++) {
cin >> a[i] >> b[i];
pref[--a[i]]++;
pref[b[i]]--;
}
partial_sum(pref,pref+2*n,pref);
for(int i=0;i<2*n;i++)
if(pref[i] >= 3) {
cout << 0;
return 0;
}
memset(cur,-1,sizeof(cur));
for(int i=0;i<n;i++)
for(int j=a[i];j<b[i];j++)
if(cur[j] == -1)
cur[j] = i;
else {
adj[cur[j]].push_back(i);
adj[i].push_back(cur[j]);
}
memset(vis,0,sizeof(vis));
int ans = 1;
for(int i=0;i<n;i++)
if(!vis[i]) {
queue<int> q;
q.push(i);
vis[i] = 1;
ans = (2 * ans) % (1'000'000'007);
while(q.size()) {
int x = q.front();
q.pop();
for(auto y: adj[x])
if(!vis[y]) {
vis[y] = 1;
q.push(y);
}
}
}
cout << ans;
}
