#include <bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
#define pb push_back
using namespace std;
typedef long long ll;
const int maxn = 1e6 + 5;
const int inf = 1e9;
const int mod = 1e9 + 7;
struct segment
{
int l, r, c;
};
segment seg[maxn];
int idl[maxn * 2], idr[maxn * 2], N;
struct seg_tree
{
vector<pair<int, int>> ST;
void init(int n)
{
ST.resize(4 * n + 5);
fill(begin(ST), end(ST), mp(-inf, 0));
}
#define lc id << 1
#define rc id << 1 | 1
void update(int id, int l, int r, int pos, int val)
{
if (l > pos || r < pos)
return;
if (l == r){
ST[id] = mp(val, pos);
return;
}
int mid = (l + r) / 2;
update(lc, l, mid, pos, val); update(rc, mid + 1, r, pos, val);
ST[id] = max(ST[lc], ST[rc]);
}
pair<int, int> getmax(int id, int l, int r, int L, int R)
{
if (l > R || L > r)
return mp(-inf, -inf);
if (L <= l && r <= R)
return ST[id];
int mid = (l + r) / 2;
return max(getmax(lc, l, mid, L, R), getmax(rc, mid + 1, r, L, R));
}
#undef lc
#undef rc
}st1, st2;
queue<pair<int, int>> Q;
void bfs(int x, int c)
{
seg[x].c = c;
pair<int, int> tmp;
tmp = st1.getmax(1, 1, 2 * N, seg[x].l + 1, seg[x].r - 1);
while (tmp.fi > seg[x].r){
int i = idl[tmp.se];
st1.update(1, 1, 2 * N, seg[i].l, -inf);
st2.update(1, 1, 2 * N, seg[i].r, -inf);
Q.emplace(i, 3 - c);
tmp = st1.getmax(1, 1, 2 * N, seg[x].l + 1, seg[x].r - 1);
}
tmp = st2.getmax(1, 1, 2 * N, seg[x].l + 1, seg[x].r - 1);
while (-tmp.fi < seg[x].l){
int i = idr[tmp.se];
st1.update(1, 1, 2 * N, seg[i].l, -inf);
st2.update(1, 1, 2 * N, seg[i].r, -inf);
Q.emplace(i, 3 - c);
tmp = st2.getmax(1, 1, 2 * N, seg[x].l + 1, seg[x].r - 1);
}
}
signed main(void)
{
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
if (fopen("A.INP", "r")){
freopen("A.INP", "r", stdin);
freopen("A.OUT", "w", stdout);
}
cin >> N;
st1.init(2 * N); st2.init(2 * N);
for (int i = 1; i <= N; ++i){
cin >> seg[i].l >> seg[i].r;
idl[seg[i].l] = i; idr[seg[i].r] = i;
st1.update(1, 1, 2 * N, seg[i].l, seg[i].r);
st2.update(1, 1, 2 * N, seg[i].r, -seg[i].l);
}
int ans = 1;
for (int i = 1; i <= N; ++i){
if (seg[i].c == 0){
st1.update(1, 1, 2 * N, seg[i].l, -inf);
st2.update(1, 1, 2 * N, seg[i].r, -inf);
Q.emplace(i, 1);
while (Q.size()){
auto now = Q.front(); Q.pop();
bfs(now.fi, now.se);
}
ans = ans * 2 % mod;
}
}
sort(seg + 1, seg + 1 + N, [&](const segment & x, const segment & y){
return x.l < y.l;
});
for (int i = 1; i <= N; ++i){
pair<int, int> c1 = st1.getmax(1, 1, 2 * N, seg[i].l, seg[i].r);
pair<int, int> c2 = st2.getmax(1, 1, 2 * N, seg[i].l, seg[i].r);
if (c1.fi != -inf && (c1.fi == seg[i].c || -c2.fi == seg[i].c)){
cout << 0;
return 0;
}
st1.update(1, 1, 2 * N, seg[i].r, seg[i].c);
st2.update(1, 1, 2 * N, seg[i].r, -seg[i].c);
}
cout << ans;
}
