#include <bits/stdc++.h>
#define ll long long
#define name "Port Facility"
#define _left id + 1, l, mid
#define _right id + 2 * (mid - l + 1), mid + 1, r
#define fi(i, a, b) for(int i = a; i <= b; ++i)
#define fid(i, a, b) for(int i = a; i >= b; --i)
#define maxn (int) (1e6 + 1)
const ll mod = 1e9 + 7;
using namespace std;
int n;
pair<int, int> a[maxn];
int cl[maxn];
struct IT {
int w, sz = 2 * maxn;
pair<int, int> st[4 * maxn];
void init(int _w) {
w = _w;
fi(i, 1, 4 * maxn - 2) st[i].first = -1e9;
}
void update(int id, pair<int, int> val) {
val.first *= w; st[id += sz] = val;
while(id != 1) {
id >>= 1;
st[id] = max(st[id * 2], st[id * 2 + 1]);
}
}
int get(int l, int r) {
pair<int, int> ans = {(int) -1e9, 0};
l += sz, r += sz;
while(l <= r) {
ans = max({ans, st[l], st[r]});
l = (l + 1) >> 1, r = (r - 1) >> 1;
}
return ans.second;
}
} StMax, StMin;
void dfs(int i, int col) {
cl[i] = col;
StMin.update(a[i].second, {(int) 1e9, 0});
StMax.update(a[i].first, {(int) -1e9, 0});
while(1) {
int it = StMin.get(a[i].first + 1, a[i].second - 1);
if(a[it].first > a[i].first || !it) break;
dfs(it, 3 - col);
}
while(1) {
int it = StMax.get(a[i].first + 1, a[i].second - 1);
if(a[it].second < a[i].second || !it) break;
dfs(it, 3 - col);
}
}
int q[maxn], P[2 * maxn];
bool check(int type) {
int top = 0;
fi(i, 1, n) {
int val = cl[i] == type ? i : -i;
P[a[i].first] = P[a[i].second] = val;
}
fi(i, 1, 2 * n) if(P[i] > 0) {
if(top && q[top] == P[i]) --top;
else q[++top] = P[i];
}
return !top;
}
void solve() {
cin >> n;
fi(i, 1, n) cin >> a[i].first >> a[i].second;
StMin.init(-1), StMax.init(1);
fi(i, 1, n) {
StMin.update(a[i].second, {a[i].first, i});
StMax.update(a[i].first, {a[i].second, i});
}
ll ans = 1;
fi(i, 1, n) if(!cl[i]) {
dfs(i, 1);
ans = ans * 2 % mod;
}
if(!check(1) || !check(2)) return cout << 0, void();
cout << ans << '\n';
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0), cout.tie(0);
if(fopen(name".inp", "r")) {
freopen(name".inp", "r", stdin);
freopen(name".out", "w", stdout);
}
solve();
}
