#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef pair <int, int> ii;
const int N = 1e6 + 6, MOD = 1e9 + 7;
int n, a[N], b[N], id[2 * N], color[N];
bool mark[N];
struct SegmentTree {
int n;
vector <int> st;
SegmentTree() {}
SegmentTree(int _n) {
this -> n = _n;
st.assign(4 * n + 5, 0);
}
int Left(int x) {return (x << 1);}
int Right(int x) {return (x << 1) + 1;}
void update(int id, int L, int R, int i, int val) {
if (L > i || R < i) return;
if (L == R) {
st[id] = val;
return;
}
int mid = (L + R) >> 1;
update(Left(id), L, mid, i, val);
update(Right(id), mid + 1, R, i, val);
st[id] = max(st[Left(id)], st[Right(id)]);
}
int get(int id, int L, int R, int i, int j) {
if (L > j || R < i) return 0;
if (L >= i && R <= j)
return st[id];
int mid = (L + R) >> 1;
return max(get(Left(id), L, mid, i, j), get(Right(id), mid + 1, R, i, j));
}
void update(int i, int val) {
update(1, 1, n, i, val);
}
int get(int i, int j) {
if (i > j) return 0;
get(1, 1, n, i, j);
}
} solver;
struct IT {
int n;
vector <int> st;
IT() {}
IT(int _n) {
this -> n = _n;
st.assign(4 * n + 5, 0);
}
int Left(int x) {return (x << 1);}
int Right(int x) {return (x << 1) + 1;}
void update(int id, int L, int R, int i, int val) {
if (L > i || R < i) return;
if (L == R) {
st[id] = val;
return;
}
int mid = (L + R) >> 1;
update(Left(id), L, mid, i, val);
update(Right(id), mid + 1, R, i, val);
st[id] = st[Left(id)] + st[Right(id)];
}
int get(int id, int L, int R, int i, int j) {
if (L > j || R < i) return 0;
if (L >= i && R <= j)
return st[id];
int mid = (L + R) >> 1;
return get(Left(id), L, mid, i, j) + get(Right(id), mid + 1, R, i, j);
}
void update(int i, int val) {
update(1, 1, n, i, val);
}
int get(int i, int j) {
if (i > j) return 0;
get(1, 1, n, i, j);
}
} dem[2];
void dfs(int u) {
mark[u] = 1;
if (dem[color[u]].get(a[u] + 1, b[u] - 1)) {
cout << 0 << endl;
exit(0);
}
while (1) {
int val = solver.get(a[u] + 1, b[u] - 1);
if (val < b[u]) break;
int v = id[val];
solver.update(a[v], 0);
color[v] = color[u] ^ 1;
dem[color[v]].update(a[v], 1);
dfs(v);
}
}
signed main() {
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> n;
solver = SegmentTree(2 * n);
dem[1] = IT(2 * n);
dem[0] = IT(2 * n);
for (int i = 1; i <= n; ++i) {
cin >> a[i] >> b[i];
solver.update(a[i], b[i]);
id[b[i]] = i;
}
int cc = 0;
for (int i = 1; i <= n; ++i) if (!mark[i]) {
dfs(i);
cc++;
}
int res = 1;
while (cc--) {
res = (res * 2) % MOD;
}
cout << res << endl;
return 0;
}
