#include <bits/stdc++.h>
using namespace std;
const int nx=2e3+5, mod=1e9+7;
int n, l[nx], r[nx], res=1, cnt, c[nx], f, vs[nx];
vector<int> d[nx];
void dfs(int u)
{
vs[u]=1;
for (auto v:d[u])
{
if (vs[v])
{
if (c[v]==c[u]) f=1;
continue;
}
c[v]=!c[u];
dfs(v);
}
}
int main()
{
cin.tie(NULL)->sync_with_stdio(false);
cin>>n;
for (int i=1; i<=n; i++) cin>>l[i]>>r[i];
for (int i=1; i<=n; i++)
{
for (int j=i+1; j<=n; j++)
{
if ((l[i]<l[j]&&r[j]<r[i])||(l[j]<l[i]&&r[i]<r[j])||r[i]<l[j]||r[j]<l[i]) continue;
d[i].push_back(j);
d[j].push_back(i);
}
}
for (int i=1; i<=n; i++) if (!vs[i]) dfs(i), res=(res*2)%mod;
if (f) cout<<0;
else cout<<res;
}
