#include <bits/stdc++.h>
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#pragma GCC optimize("unroll-loops")
#define rep(i,l,r) for (int i = l; i < r; i++)
#define repr(i,r,l) for (int i = r; i >= l; i--)
#define X first
#define Y second
#define pb push_back
#define endl '\n'
#define debug(x) cerr << #x << " : " << x << endl;
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pll;
constexpr int N = 1e6+20,mod = 1e9+7,inf = 1e9+10;
inline int mkay(int a,int b){
if (a+b >= mod) return a+b-mod;
if (a+b < 0) return a+b+mod;
return a+b;
}
inline int poww(int a,int k){
if (k < 0) return 0;
int z = 1;
while (k){
if (k&1) z = 1ll*z*a%mod;
a = 1ll*a*a%mod;
k >>= 1;
}
return z;
}
pll p[N];
int seg[N*4],a[N*2],n,cmp[N],col[N];
set<pll> en[N];
vector<int> adj[N];
void upd(int l,int r,int p,int x,int v = 1){
if (r-l == 1){
seg[v] = x;
return;
}
int m = (l+r) >> 1,u = (v << 1);
if (p < m) upd(l,m,p,x,u);
else upd(m,r,p,x,u|1);
seg[v] = seg[u]+seg[u|1];
}
bool dfs(int v,int t){
if (col[v])
return (col[v] == t);
col[v] = t;
for (int u : adj[v]) if (!dfs(u,3-t)) return 0;
return 1;
}
int main(){
ios :: sync_with_stdio(0); cin.tie(0);
cin >> n;
rep(i,1,n+1)
cin >> p[i].X >> p[i].Y;
sort(p+1,p+n+1);
int nn = 2*n;
rep(i,1,n+1) a[p[i].X] = a[p[i].Y] = i;
int mx = 0;
bool f = 1;
rep(i,1,nn+1){
if (p[a[i]].X == i){
if (mx > p[a[i]].Y) continue;
mx = p[a[i]].Y;
upd(0,n+1,a[i],1);
if (seg[1] > 2){
f = 0;
break;
}
}
else upd(0,n+1,a[i],0);
}
if (!f){
cout << 0;
return 0;
}
int cnt = 0;
set<pair<pll,int> > st;
rep(i,1,n+1){
pll g = {p[i].Y,p[i].Y};
int y = i;
cmp[i] = i;
en[y].insert({p[i].Y,i});
vector<pair<pll,int>> er;
for(pair<pll,int> x : st){
if (x.X.X < p[i].X){
er.pb(x);
cnt++;
continue;
}
if (x.X.Y > g.X)
break;
auto it = en[x.Y].lower_bound(make_pair(p[i].X,0));
pll z = *(it);
if (it == en[x.Y].end() || z.X >= p[i].Y) continue;
adj[z.Y].pb(i);
adj[i].pb(z.Y);
if (en[x.Y].upper_bound(z) != en[x.Y].end()){
pll w = *(en[x.Y].upper_bound(z));
if (w.X < p[i].Y){
adj[w.Y].pb(i);
adj[i].pb(w.Y);
}
}
er.pb(x);
g = {max(g.X,x.X.X),min(g.Y,x.X.Y)};
if (en[y].size() > en[x.Y].size()) swap(y,x.Y);
for (pll d : en[y]){
en[x.Y].insert(d);
cmp[d.Y] = x.Y;
}
en[y].clear();
y = x.Y;
}
for(pair<pll,int> x : er) st.erase(x);
st.insert({g,y});
}
rep(i,1,n+1){
if (col[i]) continue;
f &= dfs(i,1);
}
cout << ((!f) ? 0 : poww(2,st.size()+cnt));
}
