#include <bits/stdc++.h>
#define FOR(i, x, y) for(int i = x; i < y; i++)
#define F0R(i, y) FOR(i, 0, y)
#define ROF(i, x, y) for(int i = y - 1; i >= x; i--)
#define R0F(i, y) ROF(i, 0, y)
#define WTF cout << "WTF" << endl
#define ALL(x) x.begin(), x.end()
#define RALL(x) x.rbegin(), x.rend();
#define IOS ios_base::sync_with_stdio(0); cin.tie(0)
#define F first
#define S second
#define pb push_back
using namespace std;
typedef long long LL;
typedef pair<int, int> PII;
typedef pair<LL, LL> PLL;
typedef vector<int> VI;
typedef vector<LL> VLL;
typedef vector<PII> VPII;
typedef vector<PLL> VPLL;
const int N = 1e6 + 7;
const int MOD = 1e9 + 7;
const int INF = 1e9 + 7;
#define lc now << 1
#define rc now << 1 | 1
int n, f[N << 1];
bool vis[N], comp[N];
PII ns[N];
set<PII> tree[N << 3];
queue<int> keep;
stack<int> dr;
void add(int place, PII x, int now = 1, int ls = 0, int rs = (n << 1) - 1) {
tree[now].insert(x);
if (ls == rs) return;
int mid = (ls + rs) >> 1;
if (place <= mid) add(place, x, lc, ls, mid);
else add(place, x, rc, mid + 1, rs);
return;
}
void rem(int place, PII x, int now = 1, int ls = 0, int rs = (n << 1) - 1) {
tree[now].erase(x);
if (ls == rs) return;
int mid = (ls + rs) >> 1;
if (place <= mid) rem(place, x, lc, ls, mid);
else rem(place, x, rc, mid + 1, rs);
return;
}
void init() {
cin >> n;
F0R(i, n) {
cin >> ns[i].F >> ns[i].S;
ns[i].F--; ns[i].S--;
add(ns[i].F, {ns[i].S, i});
}
return;
}
void getEdge(int lq, int rq, int now = 1, int ls = 0, int rs = (n << 1) - 1) {
if (rq < lq || rq < ls || rs < lq) return;
if (lq <= ls && rs <= rq) {
if (tree[now].empty()) return;
for(PII on = *(--tree[now].end()); ; on = *(--tree[now].lower_bound(on))) {
if (on.F <= rq) break;
dr.push(on.S);
if (on == *tree[now].begin()) break;
}
return;
}
int mid = (ls + rs) >> 1;
getEdge(lq, rq, lc, ls, mid);
getEdge(lq, rq, rc, mid + 1, rs);
return;
}
void bfs(int now) {
vis[now] = 1;
comp[now] = 0;
rem(ns[now].F, {ns[now].S, now});
keep.push(now);
while(!keep.empty()) {
int on = keep.front();
keep.pop();
getEdge(ns[on].F, ns[on].S);
while(!dr.empty()) {
int x = dr.top(); dr.pop();
comp[x] = 1 ^ comp[on];
vis[x] = 1;
rem(ns[x].F, {ns[x].S, x});
keep.push(x);
}
}
return;
}
bool check() {
memset(f, 0, sizeof f);
F0R(i, n) if (!comp[i]) f[ ns[i].F ] = (i + 1), f[ ns[i].S ] = -(i + 1);
stack<int> st;
F0R(i, (n << 1)) if (f[i]) {
if (f[i] > 0) st.push(f[i]);
else {
if (st.empty() || st.top() != -f[i]) return 0;
st.pop();
}
}
memset(f, 0, sizeof f);
F0R(i, n) if (comp[i]) f[ ns[i].F ] = (i + 1), f[ ns[i].S ] = -(i + 1);
while(!st.empty()) st.pop();
F0R(i, (n << 1)) if (f[i]) {
if (f[i] > 0) st.push(f[i]);
else {
if (st.empty() || st.top() != -f[i]) return 0;
st.pop();
}
}
return 1;
}
int main() {
IOS;
init();
int ans = 1;
F0R(i, n) if (!vis[i]) {
bfs(i);
ans = (ans << 1) % MOD;
}
cout << 0 << endl;
}
