#include<bits/stdc++.h>
using namespace std;
typedef pair<int,int>pii;
#define SIZE (1<<21)
#define LOG 21
class unionfind
{
public:
int par[SIZE * 2];
int ran[SIZE * 2];
void init()
{
for (int i = 0; i<SIZE * 2; i++)
{
par[i] = i;
ran[i] = 0;
}
}
int find(int a)
{
if (a == par[a])return a;
else return par[a] = find(par[a]);
}
void unite(int a, int b)
{
//printf("%d %d\n", a, b);
a = find(a);
b = find(b);
if (a == b)return;
if (ran[a]>ran[b])
{
par[b] = a;
}
else
{
par[a] = b;
}
if (ran[a] == ran[b])ran[b]++;
}
};
unionfind uf;
void adde(int a, int b, bool f)
{
if (f)uf.unite(a * 2, b * 2), uf.unite(a * 2 + 1, b * 2 + 1);
else uf.unite(a * 2, b * 2 + 1), uf.unite(a * 2 + 1, b * 2);
}
class segtree
{
public:
vector<pii>seg[1 << (LOG + 1)];
bool isok;
void init()
{
isok = true;
for (int i = 0; i < 1 << (LOG + 1); i++)seg[i].clear();
}
void add(int beg, int end)
{
int node = 1;
int lb = 0, ub = (1 << LOG) - 1;
for (;;)
{
int m = (lb + ub) / 2;
if (end <= m)ub = m, node = node * 2;
else if (m + 1 <= beg)lb = m + 1, node = node * 2 + 1;
else
{
seg[node].push_back(make_pair(beg, end));
break;
}
}
}
void solve1(int node, int lb, int ub)
{
sort(seg[node].begin(), seg[node].end());
vector<pii>a, b;
int mini = 1000000000;
for (int i = 0; i < seg[node].size(); i++)
{
if (mini > seg[node][i].second)
{
mini = seg[node][i].second;
a.push_back(seg[node][i]);
}
else b.push_back(seg[node][i]);
}
for (int i = 1; i < b.size(); i++)if (b[i - 1].second < b[i].second)isok = false;
int pt = 0;
for (int i = 0; i < a.size(); i++)
{
for (;;)
{
if (pt == b.size())break;
if (a[i].second > b[pt].second)break;
if (a[i].first < b[pt].first)adde(a[i].first, b[pt].first, false);
pt++;
}
if (pt != 0)pt--;
}
}
int idx[SIZE], imos[SIZE];
void solve2(int node, int lb, int ub)
{
fill(idx, idx + ub - lb + 1, -1);
fill(imos, imos + seg[node].size() + 1, 0);
for (int i = 0; i < seg[node].size(); i++)idx[seg[node][i].first - lb] = i;
for (int i = 1; i < ub - lb + 1; i++)if (idx[i] == -1)idx[i] = idx[i - 1];
for (int i = 0; i < seg[node * 2].size(); i++)if (idx[seg[node * 2][i].first - lb] < idx[seg[node * 2][i].second - lb])imos[idx[seg[node * 2][i].first - lb] + 1]++, imos[idx[seg[node * 2][i].second - lb]]--;
for (int i = 0; i < seg[node * 2].size(); i++)if (idx[seg[node * 2][i].first - lb] < idx[seg[node * 2][i].second - lb])adde(seg[node * 2][i].first, seg[node][idx[seg[node * 2][i].second - lb]].first, false);
for (int i = 1; i <= seg[node].size(); i++)imos[i] += imos[i - 1];
for (int i = 0; i<int(seg[node].size()) - 1; i++)if (imos[i])adde(seg[node][i].first, seg[node][i + 1].first, true);
}
void solve3(int node, int lb, int ub)
{
for (int i = 0; i < seg[node].size(); i++)swap(seg[node][i].first, seg[node][i].second);
sort(seg[node].begin(), seg[node].end());
for (int i = 0; i < seg[node].size(); i++)swap(seg[node][i].first, seg[node][i].second);
fill(idx, idx + ub - lb + 1, -1);
fill(imos, imos + seg[node].size() + 1, 0);
for (int i = 0; i < seg[node].size(); i++)idx[seg[node][i].second - lb] = i;
for (int i = 1; i < ub - lb + 1; i++)if (idx[i] == -1)idx[i] = idx[i - 1];
for (int i = 0; i < seg[node * 2 + 1].size(); i++)if (idx[seg[node * 2 + 1][i].first - lb] < idx[seg[node * 2 + 1][i].second - lb])imos[idx[seg[node * 2 + 1][i].first - lb] + 1]++, imos[idx[seg[node * 2 + 1][i].second - lb]]--;
for (int i = 0; i < seg[node * 2 + 1].size(); i++)if (idx[seg[node * 2 + 1][i].first - lb] < idx[seg[node * 2 + 1][i].second - lb])adde(seg[node * 2 + 1][i].first, seg[node][idx[seg[node * 2 + 1][i].second - lb]].first, false);
for (int i = 1; i <= seg[node].size(); i++)imos[i] += imos[i - 1];
for (int i = 0; i<int(seg[node].size()) - 1; i++)if (imos[i])adde(seg[node][i].first, seg[node][i + 1].first, true);
}
void calc()
{
for (int i = LOG - 1; i >= 0; i--)
{
for (int j = 0; j < (1 << i); j++)
{
int node = (1 << i) + j;
solve1(node, j << (LOG - i), ((j + 1) << (LOG - i)) - 1);
solve2(node, j << (LOG - i), (j << (LOG - i)) + (1 << (LOG - 1 - i)) - 1);
solve3(node, (j << (LOG - i)) + (1 << (LOG - 1 - i)), ((j + 1) << (LOG - i)) - 1);
for (int k = 0; k < seg[node * 2].size(); k++)seg[node].push_back(seg[node * 2][k]);
for (int k = 0; k < seg[node * 2 + 1].size(); k++)seg[node].push_back(seg[node * 2 + 1][k]);
}
}
}
};
segtree tree;
int solve(int N, vector<int> A, vector<int> B) {
int num = N;
tree.init();
vector<pii>vec;
for(int i=0;i<num;i++)
{
int za = A[i], zb = B[i];
za--,zb--;
vec.push_back(make_pair(za,zb));
tree.add(za, zb);
}
uf.init();
tree.calc();
for (int i = 0; i < num; i++)if (uf.find(vec[i].first * 2) == uf.find(vec[i].first * 2 + 1))tree.isok = false;
int cnt = 0;
for (int i = 0; i < num; i++)if (uf.find(vec[i].first * 2) == vec[i].first * 2)cnt++;
for (int i = 0; i < num; i++)if (uf.find(vec[i].first * 2 + 1) == vec[i].first * 2 + 1)cnt++;
int ans=tree.isok;
for (int i = 0; i < cnt / 2; i++)ans = ans * 2 % 1000000007;
return ans;
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
int N; cin >> N;
vector<int> A(N), B(N);
for (int i = 0; i < N; i ++) {
cin >> A[i] >> B[i];
}
cout << solve(N, A, B) << '\n';
}
