//#pragma GCC optimize("Ofast,unroll-loops")
//#pragma GCC target("avx,avx2,fma,lzcnt,popcnt")
#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define pb push_back
#define pf push_front
#define ii pair<int,int>
#define ill pair<ll,ll>
#define el cout<<'\n'
#define ordered_set tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>
const ll mod=1e9+7;
const int dx[]={1,0,-1,0},dy[]={0,1,0,-1};
const int nmax=2e6;
const int inf =2e9;
void add(int &a, int b) {
a += b;
if (a >= mod) a -= mod;
if (a < 0) a += mod;
}
void sub ( int&a , int b ) { if ((a-=b) < 0 ) a += mod ; }
template<typename T> void chkmin(T& x, T y) {if(x > y) x = y;}
template<typename T> void chkmax(T& x, T y) {if(x < y) x = y;}
using namespace std;
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
int rand(int l, int r)
{
return uniform_int_distribution<int>(l, r) (rd);
}
int n;
ii range[nmax + 5];
int col[nmax + 5];
struct Tree{
vector<pair<int,int>>t;
Tree(){}
void init(int sz)
{
t.resize(4 * sz + 5,{-inf,0});
}
void update(int id,int l,int r,int pos,ii val)
{
if(l > pos || r < pos)
return;
if(l == r)
{
t[id] = val;
return;
}
int mid = (l + r) >> 1;
update(id<<1,l,mid,pos,val);
update(id<<1 | 1,mid+1,r,pos,val);
t[id] = max(t[id << 1],t[id << 1 | 1]);
}
ii get(int id,int l,int r,int u,int v)
{
if(l > v || r < u)
{
return(make_pair(-inf,0));
}
if(u <= l && r <= v)
return t[id];
int mid = (l + r) >> 1;
return max(get(id<<1,l,mid,u,v),get(id<<1 | 1,mid+1,r,u,v));
}
}treemax,treemin;
void dfs(int u,int color){
col[u] = color;
treemax.update(1,1,2*n,range[u].fi,{-inf,0});
treemin.update(1,1,2*n,range[u].se,{-inf,0});
while(true)
{
int v = treemax.get(1,1,2*n,range[u].fi,range[u].se - 1).se;
if(!v || range[v].se <= range[u].se) break;
dfs(v,3 - color);
}
while(true)
{
int v = treemin.get(1,1,2*n,range[u].fi,range[u].se - 1).se;
if(!v || range[v].fi > range[u].fi) break;
dfs(v,3 - color);
}
}
int st[nmax + 5];
int event[nmax + 5];
bool check(int type)
{
for(int i=1;i<=2*n;i++)
event[i] = 0;
for(int i=1;i<=n;i++)
if(col[i] == type)
{
event[range[i].fi] = i;
event[range[i].se] = i;
}
int top = 0;
for(int i=1;i<=2*n;i++)
{
if(event[i])
{
if(top > 0 && st[top] == event[i])
top--;
else
{
st[++top] = event[i];
}
}
}
return (top == 0);
}
signed main()
{
ios::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
cin >> n;
for(int i=1;i<=n;i++)
cin >> range[i].fi >> range[i].se;
treemax.init(2*n);
treemin.init(2*n);
for(int i=1;i<=n;i++)
{
treemax.update(1,1,2*n,range[i].fi,{range[i].se,i});
treemin.update(1,1,2*n,range[i].se,{-range[i].fi,i});
}
int ans = 1;
for(int i=1;i<=n;i++)
if(!col[i])
{
dfs(i,1);
ans = (ans * 2)%mod;
}
if(!check(1) || !check(2)){
cout << 0;
return 0;
}
cout << ans;
}
// "Can i get a kiss? And can u make it last forever?"
