#include "bits/stdc++.h"
using namespace std;
#define ar array
typedef long long ll;
const int N = 2e6 + 5;
const int mod = 1e9 + 7;
struct ST{
int tree[N << 2];
ST(){
for(int i=0;i<(N<<2);i++) tree[i] = -N;
}
void set(int i, int v, int lx = 0, int rx = N, int x = 1){
if(lx == rx){
tree[x] = v;
return;
}
int m = (lx + rx) >> 1;
if(i <= m) set(i, v, lx, m, x << 1);
else set(i, v, m + 1, rx, x << 1 | 1);
tree[x] = max(tree[x << 1], tree[x << 1 | 1]);
}
int get(int l, int r, int lx = 0, int rx = N, int x = 1){
if(lx > r || rx < l) return -N;
if(lx >= l && rx <= r) return tree[x];
int m = (lx + rx) >> 1;
return max(get(l, r, lx, m, x << 1), get(l, r, m + 1, rx, x << 1 | 1));
}
}Min, Max;
int a[N], b[N], used[N], c[N];
int id[N];
signed main(){
ios::sync_with_stdio(0); cin.tie(0);
int n; cin >> n;
for(int i=0;i<n;i++){
cin >> a[i] >> b[i];
Min.set(b[i], -a[i]);
Max.set(a[i], b[i]);
id[a[i]] = id[b[i]] = i;
}
vector<int> t[2];
function<void(int)> dfs = [&](int u){
Max.set(a[u], -N), Min.set(b[u], -N);
used[u] = 1;
t[c[u]].push_back(u);
while(true){
int i = Max.get(a[u], b[u]);
if(b[u] < i){
c[id[i]] = c[u] ^ 1;
dfs(id[i]);
continue;
}
i = -Min.get(a[u], b[u]);
if(i < a[u]){
c[id[i]] = c[u] ^ 1;
dfs(id[i]);
continue;
}
break;
}
};
auto check = [&](vector<int>& t){
for(auto i : t){
Min.set(b[i], -a[i]);
Max.set(a[i], b[i]);
}
for(auto u : t){
int i = Max.get(a[u], b[u]);
if(b[u] < i){
return true;
}
i = -Min.get(a[u], b[u]);
if(i < a[u]){
return true;
}
}
for(auto i : t){
Min.set(b[i], -N);
Max.set(a[i], -N);
}
return false;
};
int res = 1;
for(int i=0;i<n;i++){
if(used[i]) continue;
t[0].clear(), t[1].clear();
dfs(i);
if(check(t[0]) || check(t[1])){
cout<<0<<"\n";
return 0;
}
res = res * 2ll % mod;
}
cout<<res<<"\n";
}
