#include <iostream>
#include <vector>
using namespace std;
const int maxN = 1'000'000;
const int mod = 1e9 + 7;
vector<int> edge[1+maxN];
vector<int> A(1+maxN), B(1+maxN);
void add_edge(int u, int v)
{
edge[u].push_back(v);
edge[v].push_back(u);
// cerr << "edge " << u << ' ' << v << '\n';
}
bool no_sol = 0;
vector<int> color(1+maxN, -1);
int comp = 0;
void dfs(int u)
{
for(int v: edge[u])
{
if(color[v] == !color[u]) continue;
else if(color[v] == color[u]) no_sol = 1;
else
{
color[v] = !color[u];
dfs(v);
}
}
}
int main()
{
int N;
cin >> N;
vector<int> event(1+2*N);
for(int i = 1; i <= N; i++)
{
cin >> A[i] >> B[i];
event[A[i]] = +i;
event[B[i]] = -i;
}
// cerr << "check\n";
vector<int> S;
for(int e = 1; e <= 2*N; e++)
{
if(event[e] > 0) continue;
// cerr << "e = " << e << '\n';
while(!S.empty() && A[-event[e]] < A[S.back()])
{
// cerr << "popping " << S.back() << '\n';
S.pop_back();
}
// if(!S.empty())
// cerr << A[-event[e]] << ' ' << B[S.back()] << '\n';
if(!S.empty() && A[-event[e]] < B[S.back()])
add_edge(-event[e], S.back());
S.push_back(-event[e]);
}
S.clear();
for(int e = 2*N; e >= 1; e--)
{
if(event[e] < 0) continue;
while(!S.empty() && B[S.back()] < B[event[e]])
S.pop_back();
if(!S.empty() && A[S.back()] < B[event[e]])
add_edge(event[e], S.back());
S.push_back(event[e]);
}
for(int i = 1; i <= N; i++)
{
if(color[i] != -1) continue;
comp++;
color[i] = 0;
dfs(i);
}
if(no_sol == 0)
{
vector<int> T[2];
for(int e = 1; e <= 2*N; e++)
{
if(event[e] > 0)
{
T[ color[event[e]] ].push_back(event[e]);
}
else
{
if(T[ color[-event[e]] ].back() == -event[e])
T[ color[-event[e]] ].pop_back();
else
no_sol = 1;
}
}
}
if(no_sol)
{
cout << "0\n";
}
else
{
int ans = 1;
for(int x = 1; x <= comp; x++) ans = (2 * ans) % mod;
cout << ans << '\n';
}
}
