#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1e6;
const int inf = 1e9;
const int MOD = 1e9+7;
int n;
int atl[2*MAXN];
int atr[2*MAXN];
vector<int> deact;
class mintree {
public:
int mn = inf;
mintree *l = nullptr;
mintree *r = nullptr;
int lp, rp;
mintree(int lv, int rv, int arr[]) {
lp = lv;
rp = rv;
if (lp == rp) {
if (arr[lp] != -1) mn = arr[lp];
}
else {
int m = (lp+rp)/2;
l = new mintree(lp, m, arr);
r = new mintree(m+1, rp, arr);
mn = min(l->mn, r->mn);
}
}
int query(int lv, int rv) {
if (lp > rv || rp < lv) return inf;
if (lp >= lv && rp <= rv) return mn;
return min(l->query(lv, rv), r->query(lv, rv));
}
void upd(int p, int v) {
if (lp > p || rp < p) return;
if (lp == rp) {
if (v == -1) mn = inf;
else mn = v;
return;
}
l->upd(p, v);
r->upd(p, v);
mn = min(l->mn, r->mn);
}
int l_contain(int l_lim, int l_req) {
if (rp < l_lim || mn >= l_req) return inf;
if (lp == rp) return lp;
int ans = l->l_contain(l_lim, l_req);
if (ans < inf) return ans;
return r->l_contain(l_lim, l_req);
}
};
class maxtree {
public:
int mx = -1;
maxtree *l = nullptr;
maxtree *r = nullptr;
int lp, rp;
maxtree(int lv, int rv, int arr[]) {
lp = lv;
rp = rv;
if (lp == rp) {
mx = arr[lp];
}
else {
int m = (lp+rp)/2;
l = new maxtree(lp, m, arr);
r = new maxtree(m+1, rp, arr);
mx = max(l->mx, r->mx);
}
}
int query(int lv, int rv) {
if (lp > rv || rp < lv) return -1;
if (lp >= lv && rp <= rv) return mx;
return max(l->query(lv, rv), r->query(lv, rv));
}
void upd(int p, int v) {
if (lp > p || rp < p) return;
if (lp == rp) {
mx = v;
return;
}
l->upd(p, v);
r->upd(p, v);
mx = max(l->mx, r->mx);
}
};
mintree *close_contain; // min left
maxtree *far_inter; // max right
mintree *close_inter; // min left
int uf[MAXN];
int sz[MAXN];
bool flip[MAXN];
int id[2*MAXN];
int find(int i) {
if (uf[i] == -1) return i;
int np = find(uf[i]);
flip[i] ^= flip[uf[i]];
return uf[i] = np;
}
void merge(int a, int b, bool f) {
int ia = find(a);
int ib = find(b);
if (ia == ib) {
if ((flip[a]^flip[b]) != f) {
cout << '0' << endl;
exit(0);
}
return;
}
uf[ib] = ia;
sz[ia] += sz[ib];
flip[ib] = flip[a]^flip[b]^f;
}
int main() {
ios_base::sync_with_stdio(false); cin.tie(NULL);
cin >> n;
fill(atl, atl+2*n, -1);
fill(atr, atr+2*n, -1);
fill(uf, uf+n, -1);
fill(sz, sz+n, 1);
for (int i = 0; i < n; i++) {
int l, r; cin >> l >> r; l--; r--;
atr[l] = r;
atl[r] = l;
id[l] = id[r] = i;
}
close_contain = new mintree(0, 2*n-1, atl);
far_inter = new maxtree(0, 2*n-1, atr);
close_inter = new mintree(0, 2*n-1, atl);
for (int i = 0; i < 2*n; i++) {
if (atr[i] == -1) continue;
int r_cont = close_contain->l_contain(atr[i]+1, i);
assert(r_cont > atr[i]);
if (r_cont < inf) {
int mx_r = far_inter->query(i, atr[i]);
if (mx_r > r_cont) merge(id[i], id[r_cont], 0);
}
int lp = close_inter->query(atr[i]+1, r_cont-1);
while (lp <= atr[i]) {
deact.push_back(lp);
merge(id[i], id[lp], 1);
close_inter->upd(atr[lp], -1);
lp = close_inter->query(atr[i]+1, r_cont-1);
}
for (int v: deact) close_inter->upd(atr[v], v);
deact.clear();
}
int ans = 1;
for (int i = 0; i < n; i++) {
if (uf[i] == -1) {
ans *= 2;
ans %= MOD;
}
}
cout << ans << "\n";
}
