#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ld, ld> pdd;
#define fi first
#define se second
#define mp make_pair
#define fastIO ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
const int N = (int)1e6 + 2;
const int inf = (int)1e8;
const int MOD = (int)1e9 + 7;
pii tr[2][N * 4 + 51];
int k;
void update(int tv, int ps, pii nw){
ps += k;
tr[tv][ps] = nw;
ps /= 2;
while(ps > 0){
if(tv == 0) tr[tv][ps] = min(tr[tv][ps * 2], tr[tv][ps * 2 + 1]);
if(tv == 1) tr[tv][ps] = max(tr[tv][ps * 2], tr[tv][ps * 2 + 1]);
ps /= 2;
}
}
pii query(int tv, int cl, int cr){
cl += k;
cr += k;
pii cur = mp(-inf, -1);
if(tv == 0)
cur.fi = inf;
while(cl <= cr){
if(cl % 2 == 1){
if(tv==0) cur = min(cur, tr[tv][cl]);
else cur = max(cur, tr[tv][cl]);
cl ++ ;
}
if(cr % 2 == 0){
if(tv==0) cur = min(cur, tr[tv][cr]);
else cur = max(cur, tr[tv][cr]);
cr -- ;
}
cl /= 2;
cr /= 2;
}
return cur;
}
pii cl[N * 2];
pii cr[N * 2];
pii q[N];
int bit[N];
void dfs(int u, int b){
bit[u] = b;
update(0, q[u].se, mp(inf, -1));
update(1, q[u].fi, mp(-inf, -1));
int l = q[u].fi, r = q[u].se;
pii cur;
while(1){
cur = query(0, l, r);
if(cur.se == -1 || cur.fi >= l)
break;
dfs(cur.se, !b);
}
while(1){
cur = query(1, l, r);
if(cur.se == -1 || cur.fi <= r){
break;
}
dfs(cur.se, !b);
}
}
int sum[2][N * 4];
void upd(int bt, int id, int x){
id += k;
while(id > 0){
sum[bt][id] += x;
id /= 2;
}
}
int qry(int bt, int l, int r){
l += k;
r += k;
int res = 0;
while(l <= r){
if(l % 2 == 1) res += sum[bt][l ++ ];
if(r % 2 == 0) res += sum[bt][r -- ];
l /= 2;
r /= 2;
}
return res;
}
int main(){
fastIO;
for(int i = 0 ; i < N * 2; i ++ )
cl[i] = mp(inf, -1), cr[i] = mp(-inf, -1);
int n;
cin >> n;
k = n * 2;
for(int i = 0 ; i < k ; i ++ ){
update(0, i, mp(+inf, -1));
update(1, i, mp(-inf, -1));
}
for(int i = 0 ; i < n; i ++ ){
cin >> q[i].fi >> q[i].se;
q[i].fi -- ;
q[i].se -- ;
cl[q[i].se] = mp(q[i].fi, i);
cr[q[i].fi] = mp(q[i].se, i);
bit[i] = -1;
update(0, q[i].se, cl[q[i].se]);
update(1, q[i].fi, cr[q[i].fi]);
}
int ans = 1;
for(int i = 0 ; i < k ; i ++ ){
if(bit[i] == -1){
dfs(i, 0);
ans = (ans * 2ll) % MOD;
}
}
for(int i = 0 ; i < n; i ++ ){
upd(bit[i], q[i].se, +1);
}
for(int i = k - 1; i >= 0 ; i -- ){
if(cr[i].se != -1){
upd(bit[cr[i].se], cr[i].fi, -1);
if(qry(bit[cr[i].se], i, cr[i].fi) > 0){
ans = 0;
}
}
}
cout << ans << "\n";
return 0;
}
