/* Bismillahir Rahmanir Rahim */
#include <bits/stdc++.h>
using namespace std;
typedef pair<int, int> pii;
const int N = 2000005;
const int oo = 1e9;
void scanF(int &x){
register int c = getchar_unlocked();
x = 0;
for(;(c<48 || c>57);c = getchar_unlocked());
for(;c>47 && c<58;c = getchar_unlocked()) {x = (x<<1) + (x<<3) + c - 48;}
}
int n, st[N], en[N];
int lf[N], rf[N], idx[N];
int col[N], vis[N];
struct segtree{
int n;
pii mn[N*4], mx[N*4];
void build(int _n){
n = 2 * _n;
for(int i = 1; i <= n; i++){
mn[i + n - 1] = {lf[i], idx[i]};
mx[i + n - 1] = {rf[i], idx[i]};
}
for(int i = n - 1; i > 0; --i){
mn[i] = min(mn[i << 1], mn[i << 1 | 1]);
mx[i] = max(mx[i << 1], mx[i << 1 | 1]);
}
}
void modify(int pos){
pos = pos - 1 + n;
mn[pos] = {+oo, +oo};
mx[pos] = {-oo, -oo};
while(pos > 1){
mn[pos >> 1] = min(mn[pos], mn[pos ^ 1]);
mx[pos >> 1] = max(mx[pos], mx[pos ^ 1]);
pos >>= 1;
}
}
pii query_max(int l, int r){;
--l;
pii ret = {-oo, -oo};
for(l += n, r += n; l < r; l >>= 1, r >>= 1){
if(l & 1) ret = max(ret, mx[l++]);
if(r & 1) ret = max(ret, mx[--r]);
}
return ret;
}
pii query_min(int l, int r){;
--l;
pii ret = {+oo, +oo};
for(l += n, r += n; l < r; l >>= 1, r >>= 1){
if(l & 1) ret = min(ret, mn[l++]);
if(r & 1) ret = min(ret, mn[--r]);
}
return ret;
}
} tree;
void dfs(int at){
vis[at] = 1;
tree.modify(st[at]);
tree.modify(en[at]);
while(1){
pii f = tree.query_min(st[at], en[at]);
if(f.first >= st[at]) break;
col[f.second] = col[at] ^ 1;
dfs(f.second);
}
while(1){
pii f = tree.query_max(st[at], en[at]);
if(f.first <= en[at]) break;
col[f.second] = col[at] ^ 1;
dfs(f.second);
}
}
vector<int>g[N];
int flag;
int t[N*4];
void update(int b, int e, int node, int pos, int val){
if(b == e){
t[node] ^= (1 << val);
return;
}
int mid = (b + e) / 2, l = 2 * node, h = l + 1;
if(pos <= mid) update(b, mid, l, pos, val);
else update(mid+1, e, h, pos, val);
t[node] = t[l] | t[h];
}
int get(int b, int e, int node, int x, int y){
if(y < b ||e < x) return 0;
if(b >= x && e <= y) return t[node];
int mid = (b + e) / 2, l = 2 * node, h = l + 1;
return get(b, mid, l, x, y) | get(mid+1, e, h, x, y);
}
bool check(){
for(int i=1;i<=n+n;i++){
if(st[idx[i]] == i){
update(1, n+n, 1, st[idx[i]], col[idx[i]]);
}
else{
int g1 = get(1, n+n, 1, st[idx[i]]+1, en[idx[i]]);
int g2 = 1 << col[idx[i]];
if(g1 & g2) return false;
update(1, n+n, 1, st[idx[i]], col[idx[i]]);
}
}
return true;
}
int main(){
scanF(n);
for(int i=1;i<=n;i++){
scanF(st[i]);
scanF(en[i]);
lf[en[i]] = st[i];
lf[st[i]] = +oo;
rf[st[i]] = en[i];
rf[en[i]] = -oo;
idx[st[i]] = i;
idx[en[i]] = i;
}
tree.build(n);
int comp = 0;
for(int i=1;i<=n;i++){
if(!vis[i]){
dfs(i);
++comp;
}
}
if(check() == false) printf("0\n");
else{
long long ret = 1LL;
long long mod = 1e9 + 7;
for(int i=1;i<=comp;i++){
ret *= 2LL;
ret %= mod;
}
printf("%lld\n", ret);
}
return 0;
}
