#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
using namespace std;
#pragma warning (disable: 4996)
class SegmentTree {
public:
vector<vector<pair<int, int>>> dat;
vector<int> A;
vector<int> I;
int size_ = 1;
void init(int sz) {
while (size_ <= sz) size_ *= 2;
dat.resize(size_ * 2, vector<pair<int, int>>(0, make_pair(0, 0)));
A.resize(size_ * 2, 0);
}
void add(int px, int py, int ind) {
px += size_;
while (px >= 1) {
dat[px].push_back(make_pair(py, ind));
px >>= 1;
}
}
void query_(int l, int r, int x, int a, int b, int u) {
if (l <= a && b <= r) {
if (A[u] < dat[u].size() && dat[u][A[u]].first < x) {
int pos1 = A[u];
int pos2 = lower_bound(dat[u].begin(), dat[u].end(), make_pair(x, 0)) - dat[u].begin();
for (int i = pos1; i < pos2; i++) I.push_back(dat[u][i].second);
A[u] = pos2;
}
return;
}
if (b <= l || r <= a) return;
query_(l, r, x, a, (a + b) >> 1, u * 2);
query_(l, r, x, (a + b) >> 1, b, u * 2 + 1);
}
vector<int> query(int cl, int cr, int x) {
// [cl, cr) で x 未満のものを全て push する
I.clear();
query_(cl, cr, x, 0, size_, 1);
return I;
}
};
int N, L[1 << 20], R[1 << 20], f[1 << 21], col[1 << 20];
vector<pair<int, int>> A1, A2;
SegmentTree Z1, Z2;
int main() {
scanf("%d", &N);
for (int i = 1; i <= N; i++) {
scanf("%d%d", &L[i], &R[i]);
A1.push_back(make_pair(L[i], i)); f[L[i]] = i;
A2.push_back(make_pair(R[i], i)); f[R[i]] = -i;
}
sort(A1.begin(), A1.end());
sort(A2.begin(), A2.end()); reverse(A2.begin(), A2.end());
Z1.init(N * 2 + 1); for (int i = 0; i < A2.size(); i++) { int id = A2[i].second; Z1.add(L[id], -R[id], id); }
Z2.init(N * 2 + 1); for (int i = 0; i < A1.size(); i++) { int id = A1[i].second; Z2.add(R[id], L[id], id); }
for (int i = 1; i <= N; i++) { col[i] = -1; }
queue<int>Q; int cnts = 0;
for (int t = 1; t <= N; t++) {
if (col[t] != -1) continue;
col[t] = 0; Q.push(t); cnts++;
while (!Q.empty()) {
int pos = Q.front(); Q.pop();
vector<int> I1 = Z1.query(L[pos], R[pos], -R[pos]);
vector<int> I2 = Z2.query(L[pos], R[pos], L[pos]);
for (int i = 0; i < I1.size(); i++) { if (col[I1[i]] == -1) { col[I1[i]] = (col[pos] ^ 1); Q.push(I1[i]); } }
for (int i = 0; i < I2.size(); i++) { if (col[I2[i]] == -1) { col[I2[i]] = (col[pos] ^ 1); Q.push(I2[i]); } }
}
}
vector<int> S1, S2; bool flag = false;
for (int i = 1; i <= 2 * N; i++) {
int id = abs(f[i]);
if (f[i] > 0) {
if (col[id] == 0) S1.push_back(id);
if (col[id] == 1) S2.push_back(id);
}
if (f[i] < 0) {
if (col[id] == 0) { if (S1.size() == 0 || S1[S1.size() - 1] != id) flag = true; else S1.pop_back(); }
if (col[id] == 1) { if (S2.size() == 0 || S2[S2.size() - 1] != id) flag = true; else S2.pop_back(); }
}
}
int ans = 1; for (int i = 1; i <= cnts; i++) { ans *= 2; ans %= 1000000007; }
if (flag == true) ans = 0;
cout << ans << endl;
return 0;
}
