//#include "grid_encoding.h"
#include <bits/stdc++.h>
using namespace std;
#define ff first
#define ss second
#define bl ' '
#define endl '\n'
#define all(v) (v).begin(), (v).end()
#define comp(v) (v).erase(unique(all(v)), (v).end())
#define lbd(v,x) lower_bound(all(v), (x))-(v).begin()
#define ubd(v,x) upper_bound(all(v), (x))-(v).begin()
typedef long long ll;
typedef pair<int, int> pi;
typedef pair<pi, int> pii;
typedef pair<int, pi> ipi;
typedef pair<pi, pi> pipi;
typedef pair<ll, ll> pll;
const int MAXN = 100100*10;
const ll MOD = 1e9+7;
const ll INF = 2e9;
int par[MAXN];
int root(int x) {return par[x]==x?x:par[x]=root(par[x]);}
void merge(int x, int y) {
x = root(x), y = root(y);
if(x^y) par[x]=y;
}
struct DsuSegTree {
int tree[MAXN*2*4];
int lazy[MAXN*2*4];
void init() {
memset(tree, -1, sizeof tree);
memset(lazy, -1, sizeof lazy);
}
void prop(int node, int s, int e) {
if(lazy[node] != -1 && tree[node] != -1) {
if(s != e) {
for(auto x : {node<<1, node<<1|1}) {
if(lazy[x] != -1) merge(lazy[x], lazy[node]);
lazy[x] = lazy[node];
}
} else {
merge(tree[node], lazy[node]);
}
} lazy[node] = -1;
}
void update(int node, int s, int e, int l, int r, int val) {
prop(node, s, e);
if(e < l || r < s) return;
if(l <= s && e <= r) {
lazy[node] = val;
prop(node, s, e);
return;
}
int mid=s+e>>1;
update(node<<1, s, mid, l, r, val); update(node<<1|1, mid+1, e, l, r, val);
tree[node] = max(tree[node<<1], tree[node<<1|1]);
}
void set(int node, int s, int e, int idx, int val) {
prop(node, s, e);
if(e < idx || idx < s) return;
if(s == e) {
tree[node] = val; return;
}
int mid=s+e>>1;
set(node<<1, s, mid, idx, val); set(node<<1|1, mid+1, e, idx, val);
tree[node] = max(tree[node<<1], tree[node<<1|1]);
}
void clean(int node, int s, int e) {
prop(node, s, e);
if(s == e) return;
int mid = s+e>>1;
clean(node<<1, s, mid); clean(node<<1|1, mid+1, e);
}
} dsuseg;
struct SegTree {
int cnt[MAXN*2*4];
int sum[MAXN*2*4];
void update(int node, int s, int e, int idx, int val) {
if(e < idx || idx < s) return;
if(s == e) {
cnt[node] = 1;
sum[node] = val;
return;
}
int mid=s+e>>1;
update(node<<1, s, mid, idx, val); update(node<<1|1, mid+1, e, idx, val);
cnt[node] = cnt[node<<1] + cnt[node<<1|1];
sum[node] = sum[node<<1] + sum[node<<1|1];
}
pi solve(int node, int s, int e, int l, int r) {
if(e < l || r < s) return pi(0,0);
if(l <= s && e <= r) return {cnt[node], sum[node]};
int mid=s+e>>1;
pi x = solve(node<<1, s, mid, l, r), y = solve(node<<1|1, mid+1, e, l, r);
return pi(x.ff+y.ff, x.ss+y.ss);
}
} seg;
struct Inv {
int l,r,x;
} arr[MAXN];
vector<int> v, w[MAXN];
vector<Inv> tmp;
int main() {
int n; cin>>n;
for(int i=0; i<n; i++) {
cin>>arr[i].l>>arr[i].r; arr[i].x = i;
} sort(arr, arr+n, [&](Inv &a, Inv &b){return a.l<b.l;});
for(int i=0; i<n; i++) par[i] = i;
dsuseg.init();
for(int i=0; i<n; i++) {
dsuseg.update(1, 1, n<<1, arr[i].l, arr[i].r, arr[i].x);
dsuseg.set(1, 1, n<<1, arr[i].r, arr[i].x);
} dsuseg.clean(1, 1, n<<1);
for(int i=0; i<n; i++) v.push_back(root(i));
sort(all(v)); comp(v);
int sz = v.size();
ll res = 1; for(int i=0; i<sz; i++) res=(res<<1)%MOD;
sort(arr, arr+n, [&](Inv &a, Inv &b){return a.x<b.x;});
for(int i=0; i<n; i++) w[lbd(v, root(i))].push_back(i);
for(int i=0; i<sz; i++) {
tmp.clear();
for(int x : w[i]) tmp.push_back(arr[x]);
sort(all(tmp), [&](Inv &a, Inv &b){return a.l<b.l;});
for(auto &x : tmp) {
pi t = seg.solve(1, 1, n<<1, x.l, x.r);
if(t.ff == 0) {
seg.update(1, 1, n<<1, x.r, 1);
} else if(t.ss == t.ff) {
seg.update(1, 1, n<<1, x.r, -1);
} else if(t.ss == -t.ff) {
seg.update(1, 1, n<<1, x.r, 1);
} else {
cout << 0; return 0;
}
}
} cout << res;
}
