#include "bits/stdc++.h"
using namespace std;
#define for_(i, s, e) for (int i = s; i < (int) e; i++)
#define for__(i, s, e) for (ll i = s; i < e; i++)
typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> ii;
// #define endl '\n'
const ll mod = 1e9+7;
ll modpow(ll a, ll b) {
ll res = 1;
while (b) {
if (b & 1) res = (res * a) % mod;
a = (a * a) % mod;
b >>= 1;
}
return res;
}
class UFDS {
public:
vi p, rank, sz; int count = 0;
vector<ii> ends;
UFDS(vector<ii> &nums) {
int n = nums.size();
p.resize(n); rank.resize(n); sz.resize(n, 1); ends.resize(n);
for_(i, 0, n) {
p[i] = i;
ends[i] = {nums[i].second, -1};
}
count = n;
}
int getParent(int i) {
return (p[i] == i) ? i : (p[i] = getParent(p[i]));
}
void join(int i, int j) {
int a = getParent(i), b = getParent(j);
// cout << "joining " << a << " " << b << endl;
if (a == b) return;
vi vals = {ends[a].first, ends[a].second, ends[b].first, ends[b].second};
sort(vals.begin(), vals.end(), greater<int>());
count -= 1;
if (rank[a] > rank[b]) {
p[b] = a;
} else {
p[a] = b;
if (rank[a] == rank[b]) rank[b] += 1;
}
ends[p[a]] = {vals[0], vals[1]};
}
};
// const int INF = 1e9;
int main() {
#ifdef shiven
freopen("test.in", "r", stdin);
#endif
ios_base::sync_with_stdio(false);
cin.tie(0);
int n; cin >> n;
vector<ii> nums(n);
for_(i, 0, n) cin >> nums[i].first >> nums[i].second;
sort(nums.begin(), nums.end());
bool valid = true;
UFDS ufds(nums);
set<ii> s; // {end pt, idx}
for_(i, 0, n) {
int lastComp = -1;
if (s.size()) {
auto pta = s.lower_bound({nums[i].first, 0}), ptb = s.lower_bound({nums[i].second, 0});
if (ptb != s.begin()) ptb--;
if ((*ptb).first > nums[i].first and (*ptb).first < nums[i].second) lastComp = (*ptb).second;
// cout << i << " joins element with end " << (*ptb).first << " (" << (*ptb).second << ")" << endl;
auto ptc = pta == s.end() ? pta : next(pta);
bool first = true;
while ((*pta).first < (*ptb).first) {
if (first and ufds.ends[ufds.getParent((*pta).second)].second > nums[i].first) {
valid = false;
// cout << "stopping because of ends " << ufds.ends[ufds.getParent((*pta).second)].second << " and " << ufds.ends[ufds.getParent((*pta).second)].first << " being in same component " << endl;
}
else if (ufds.ends[ufds.getParent((*ptc).second)].second > nums[i].first) {
// cout << "stopping because of ends " << ufds.ends[ufds.getParent((*ptc).second)].second << " and " << ufds.ends[ufds.getParent((*ptc).second)].first << " being in same component " << endl;
valid = false;
}
if (!valid) {
break;
}
ufds.join((*pta).second, (*ptc).second);
s.erase(pta);
pta = ptc;
ptc = next(ptc);
first = false;
}
}
if (!valid) break;
s.insert({nums[i].second, i});
if (lastComp != -1) ufds.join(lastComp, i);
}
if (valid) cout << modpow(2, ufds.count);
else cout << 0;
cout << endl;
return 0;
}
