//In the name of Allah :)
#include <bits/stdc++.h>
using namespace std;
string to_string(char c) { return string(1,c); }
string to_string(bool b) { return b ? "true" : "false"; }
string to_string(const char* s) { return (string)s; }
string to_string(string s) { return s; }
string to_string(vector<bool> v) {
string res = "{"; for(int i = 0; i < (int)v.size(); i++) res += char('0'+v[i]);
res += "}"; return res; }
template<size_t SZ> string to_string(bitset<SZ> b) {
string res = ""; for(size_t i = 0; i < SZ; i++) res += char('0'+b[i]);
return res; }
template<class A, class B> string to_string(pair<A,B> p);
template<class T> string to_string(T v) { // containers with begin(), end()
bool fst = 1; string res = "{";
for (const auto& x: v) {
if (!fst) res += ", ";
fst = 0; res += to_string(x);
}
res += "}"; return res;
}
template<class A, class B> string to_string(pair<A,B> p) {
return "("+to_string(p.first)+", "+to_string(p.second)+")"; }
void DBG() { cerr << "]" << endl; }
template<class H, class... T> void DBG(H h, T... t) {
cerr << to_string(h); if (sizeof...(t)) cerr << ", ";
DBG(t...); }
#ifdef LOCAL // compile with -DLOCAL
#define wis(...) cerr << "LINE(" << __LINE__ << ") -> [" << #__VA_ARGS__ << "] : [", DBG(__VA_ARGS__)
#else
#define wis(...) 0
#endif
typedef long long ll;
#define all(x) (x).begin(), (x).end()
const int MAXN = 2e6 + 10, INF = 1e9, MOD = 1e9 + 7;
int n;
struct SegTree {
bool t;
int seg[MAXN << 2];
SegTree (bool _t) {
t = _t;
if (t) {
memset(seg, 63, sizeof(seg));
}
}
int merge (int x, int y) {
if (t) {
return min(x, y);
}
return max(x, y);
}
void update (int nd, int cl, int cr, int ind, int x) {
if (cr - cl == 1) {
seg[nd] = x;
return;
}
int L = nd << 1, R = L | 1, mid = (cl + cr) >> 1;
if (ind < mid) {
update(L, cl, mid, ind, x);
}
else {
update(R, mid, cr, ind, x);
}
seg[nd] = merge(seg[L], seg[R]);
}
inline void update (int ind, int x) {
update(1, 0, n + n + 1, ind, x);
}
int get (int nd, int cl, int cr, int l, int r) {
if (cl == l && cr == r) {
return seg[nd];
}
int L = nd << 1, R = L | 1, mid = (cl + cr) >> 1, res = t ? INF : 0;
if (l < mid) {
res = merge(res, get(L, cl, mid, l, min(mid, r)));
}
if (r > mid) {
res = merge(res, get(R, mid, cr, max(l, mid), r));
}
return res;
}
inline int get (int l, int r) {
return get(1, 0, n + n + 1, l, r);
}
} seg1(1), seg2(0);
int l[MAXN], r[MAXN], type[MAXN], pw[MAXN], comp;
vector<int> adj[MAXN];
vector<pair<int, int>> ver;
bitset<MAXN> mark, color;
void dfs (int v, bool c) {
assert(mark[v] == 0);
int u;
mark[v] = 1;
ver.push_back({l[v], r[v]});
color[v] = c;
seg1.update(r[v], INF);
seg2.update(l[v], 0);
while ((u = seg1.get(l[v], r[v])) < l[v]) {
dfs(type[u], c ^ 1);
}
while ((u = seg2.get(l[v], r[v])) > r[v]) {
dfs(type[u], c ^ 1);
}
}
int main() {
ios::sync_with_stdio(0);
#ifndef LOCAL
cin.tie(0);
#endif
pw[0] = 1;
for (int i = 1; i < MAXN; i++) {
pw[i] = 2 * pw[i - 1] % MOD;
}
cin >> n;
for (int i = 0; i < n; i++) {
cin >> l[i] >> r[i];
type[l[i]] = type[r[i]] = i;
seg1.update(r[i], l[i]);
seg2.update(l[i], r[i]);
}
for (int i = 0; i < n; i++) {
if (!mark[i]) {
comp++;
dfs(i, 0);
vector<int> tmp, stk[2];
for (auto x : ver) {
tmp.push_back(x.first);
tmp.push_back(x.second);
}
ver.clear();
sort(all(tmp));
for (int x : tmp) {
int ind = type[x];
if (l[ind] == x) {
stk[color[ind]].push_back(ind);
}
else {
if (stk[color[ind]].back() != ind) {
cout << 0 << '\n';
return 0;
}
else {
stk[color[ind]].pop_back();
}
}
}
}
}
cout << pw[comp] << '\n';
}
