/* code by the cute ~~Dengdualang~~ PixelCat owo */
/* as cute as nacho neko (aka. my wife)! */
/* Nhade stay for a night here */
/* 183234 deng deng deng pixelcat oops */
/* (yang wang yesu)*2 */
/* ^ some weird stuff. nvm =w= */
// #pragma GCC optimize("O4,unroll-loops,no-stack-protector")
// #pragma GCC target("avx,avx2,sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,fma")
#include <bits/stdc++.h>
#define int LL //__int128
#define double long double
using namespace std;
using LL = long long;
using LLL = __int128_t;
using uLL = unsigned long long;
using pii = pair<int, int>;
#define For(i, a, b) for (int i = a; i <= b; i++)
#define Fors(i, a, b, s) for (int i = a; i <= b; i += s)
#define Forr(i, a, b) for (int i = a; i >= b; i--)
#define F first
#define S second
#define L(id) (id * 2 + 1)
#define R(id) (id * 2 + 2)
#define LO(x) (x & (-x))
#define eb emplace_back
#define all(x) x.begin(), x.end()
#define sz(x) ((int)x.size())
#define mkp make_pair
// #define MOD (int)(998244353)
#define MOD (int)((LL)1'000'000'007)
#define INF (int)(4e18)
// #define INF 1e9
#define EPS (1e-6)
#ifdef NYAOWO
#include "library/debug.hpp"
inline void USACO(const string &s) {
cerr << "USACO: " << s << "\n";
}
#else
#define debug(...)
inline void timer() {}
inline void USACO(const string &s) {
freopen((s + ".in").c_str(), "r", stdin);
freopen((s + ".out").c_str(), "w", stdout);
}
#endif
inline void NYA() {
ios::sync_with_stdio(false);
cin.tie(0);
}
inline int gcd(int a, int b) {
return __gcd(a, b);
}
inline int lcm(int a, int b) {
return a / gcd(a, b) * b;
}
int fpow(int b, int p, const int &mod) {
int ans = 1;
while (p) {
if (p & 1) ans = ans * b % mod;
p >>= 1;
b = b * b % mod;
}
return ans;
}
int fpow(int b, int p) {
return fpow(b, p, MOD);
}
template <typename T>
inline void chmin(T &_a, const T &_b) {
if (_b < _a) _a = _b;
}
template <typename T>
inline void chmax(T &_a, const T &_b) {
if (_b > _a) _a = _b;
}
// mt19937_64 rng(
// chrono::steady_clock::now().time_since_epoch().count());
struct Node{
Node *l,*r;
int tag;
vector<pair<Node*,int>> adj;
Node():l(nullptr),r(nullptr),tag(0){}
Node(const Node* nd){
if(nd){
l=nd->l; r=nd->r;
}else{
l=r=nullptr;
}
tag=0;
}
};
Node* ptr[1000010];
Node* rt[1000010];
Node* update(Node *ori,int l,int r,int p,int x){
Node* nd=new Node(ori);
if(l==r){
ptr[x]=nd;
return nd;
}
int m=(l+r)/2;
if(p<=m) nd->l=update(nd->l,l,m,p,x);
else nd->r=update(nd->r,m+1,r,p,x);
return nd;
}
void link(Node *seg,int l,int r,Node *nd,int L,int R){
if(!seg) return;
if(l>R || r<L) return;
if(l>=L && r<=R){
seg->adj.eb(nd,1);
nd->adj.eb(seg,1);
return;
}
int m=(l+r)/2;
link(seg->l,l,m,nd,L,R);
link(seg->r,m+1,r,nd,L,R);
}
void soft(Node *seg,bool owo){
if(!seg || seg->tag==-1) return;
seg->tag=-1;
owo=owo || (sz(seg->adj)!=0);
if(owo){
if(seg->l){
seg->adj.eb(seg->l,0);
seg->l->adj.eb(seg,0);
}
if(seg->r){
seg->adj.eb(seg->r,0);
seg->r->adj.eb(seg,0);
}
}
soft(seg->l,owo);
soft(seg->r,owo);
}
bool dfs(Node* nd,int c){
if(!nd) return true;
if(nd->tag!=-1) return nd->tag==c;
nd->tag=c;
bool res=true;
for(auto &i:nd->adj){
res=res&&dfs(i.F,(i.S?1-c:c));
}
return res;
}
int32_t main() {
NYA();
// nyaacho >/////<
// miku sama bless me >/////<
int n; cin>>n;
// assert(n<=2000);
vector<pii> v(n);
for(auto &i:v) cin>>i.F>>i.S;
sort(all(v));
rt[0]=nullptr;
For(i,0,n-1){
rt[i+1]=update(rt[i],1,n*2,v[i].S,i);
link(rt[i+1],1,n*2,ptr[i],v[i].F+1,v[i].S-1);
}
Forr(i,n,1) soft(rt[i],false);
int ans=1;
For(i,0,n-1){
if(ptr[i]->tag==-1){
ans+=ans;
if(ans>=MOD) ans-=MOD;
if(!dfs(ptr[i],1)) ans=0;
}
}
cout<<ans<<"\n";
return 0;
}
