#include <bits/stdc++.h>
#define lsb(x) (x & (-x))
#define ll long long
#define ull unsigned long long
// 217
// 44
using namespace std;
const int MOD = (int) 1e9 + 7;
const int INF = (int) 1e9;
const int MAXN = (int) 1e6;
inline void mod(int &x) {
if(x >= MOD)
x -= MOD;
}
struct SegTree {
int aint[8 * MAXN + 1];
int n;
inline void init(int _n) {
n = _n;
for(int i = 1; i <= 4 * n; i++) {
aint[i] = -INF;
}
}
void update(int nod, int left, int right, int pos, int cur) {
if(left == right) {
aint[nod] = cur;
}
else {
int mid = (left + right) / 2;
if(pos <= mid) update(2 * nod, left, mid, pos, cur);
else update(2 * nod + 1, mid + 1, right, pos, cur);
aint[nod] = max(aint[2 * nod], aint[2 * nod + 1]);
}
}
int query(int nod, int left, int right, int l, int r) {
if(l <= left && right <= r) {
return aint[nod];
}
else {
int mid = (left + right) / 2;
int ans = -INF;
if(l <= mid) ans = max(ans, query(2 * nod, left, mid, l, r));
if(mid < r) ans = max(ans, query(2 * nod + 1, mid + 1, right, l, r));
return ans;
}
}
void update(int pos, int cur) {
update(1, 1, n, pos, cur);
}
int query(int l, int r) {
return query(1, 1, n, l, r);
}
};
SegTree stl, str;
pair <int, int> arr[MAXN + 1];
int who[2 * MAXN + 1];
bool vis[MAXN + 1], col[MAXN + 1];
int n;
void dfs(int nod, int c) {
col[nod] = c;
vis[nod] = 1;
while(1) {
int cur = str.query(arr[nod].first, arr[nod].second);
if(cur <= arr[nod].second) {
break;
}
int id = who[cur];
str.update(arr[id].first, -INF);
if(vis[id] == 0) {
dfs(id, c ^ 1);
}
}
while(1) {
int cur = -stl.query(arr[nod].first, arr[nod].second);
if(cur >= arr[nod].first) {
break;
}
int id = who[cur];
stl.update(arr[id].second, -INF);
if(vis[id] == 0) {
dfs(id, c ^ 1);
}
}
}
struct Fenwick {
int aib[2 * MAXN + 1];
int n;
inline void init(int _n) {
n = _n;
for(int i = 1; i <= n; i++) {
aib[i] = 0;
}
}
inline void update(int pos) {
for(int i = pos; i <= n; i += lsb(i)) {
aib[i]++;
}
}
inline int query(int pos) {
int ans = 0;
for(int i = pos; i > 0; i -= lsb(i)) {
ans += aib[i];
}
return ans;
}
inline int sum(int l, int r) {
return query(r) - query(l - 1);
}
};
const int MAXBUF = (1 << 17);
char buf[MAXBUF];
int pbuf = MAXBUF;
inline char nextch() {
if(pbuf == MAXBUF) {
fread(buf, 1, MAXBUF, stdin);
pbuf = 0;
}
return buf[pbuf++];
}
inline int getnr() {
char ch = nextch();
while(!isdigit(ch)) {
ch = nextch();
}
int nr = 0;
while(isdigit(ch)) {
nr = nr * 10 + ch - '0';
ch = nextch();
}
return nr;
}
int main() {
//ifstream cin("A.in");
//ofstream cout("A.out");
int i;
//ios::sync_with_stdio(false);
//cin.tie(0), cout.tie(0);
n = getnr();
stl.init(2 * n), str.init(2 * n);
for(i = 1; i <= n; i++) {
arr[i].first = getnr();
arr[i].second = getnr();
str.update(arr[i].first, arr[i].second);
stl.update(arr[i].second, -arr[i].first);
who[arr[i].first] = who[arr[i].second] = i;
}
int ans = 1;
for(i = 1; i <= n; i++) {
if(vis[i] == 0) {
dfs(i, 0);
ans *= 2;
mod(ans);
}
}
Fenwick fen[2];
for(i = 0; i < 2; i++) {
fen[i].init(2 * n);
}
vector <int> ord(n + 1);
iota(ord.begin(), ord.end(), 0);
sort(ord.begin(), ord.end(), [&](const int &a, const int &b) {
return arr[a].first < arr[b].first;
});
for(i = 1; i <= n; i++) {
int id = ord[i];
if(fen[col[id]].sum(arr[id].first, arr[id].second) > 0) {
ans = 0;
break;
}
fen[col[id]].update(arr[id].second);
}
cout << ans;
//cin.close();
//cout.close();
return 0;
}
